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The Boeing 737 is a
narrow-body aircraft A narrow-body aircraft or single-aisle aircraft is an airliner arranged along a single aisle, permitting up to 6-abreast seating in a cabin less than in width. In contrast, a wide-body aircraft is a larger airliner usually configured with mul ...
produced by
Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and ...
at its Renton Factory in
Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...
. Developed to supplement the
Boeing 727 The Boeing 727 is an American narrow-body airliner that was developed and produced by Boeing Commercial Airplanes. After the heavy 707 quad-jet was introduced in 1958, Boeing addressed the demand for shorter flight lengths from smaller air ...
on short and thin routes, the
twinjet A twinjet or twin-engine jet is a jet aircraft powered by two engines. A twinjet is able to fly well enough to land with a single working engine, making it safer than a single-engine aircraft in the event of failure of an engine. Fuel efficien ...
retains the 707 fuselage width and six abreast seating with two underwing
turbofan The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which ac ...
s. Envisioned in 1964, the initial 737-100 made its first flight in April 1967 and entered service in February 1968 with
Lufthansa Deutsche Lufthansa AG (), commonly shortened to Lufthansa, is the flag carrier of Germany. When combined with its subsidiaries, it is the second- largest airline in Europe in terms of passengers carried. Lufthansa is one of the five founding ...
. The lengthened 737-200 entered service in April 1968, and evolved through four generations, offering several variants for 85 to 215 passengers. The 737-100/200 original variants were powered by
Pratt & Whitney JT8D The Pratt & Whitney JT8D is a low-bypass (0.96 to 1) turbofan engine introduced by Pratt & Whitney in February 1963 with the inaugural flight of the Boeing 727. It was a modification of the Pratt & Whitney J52 turbojet engine which powered the ...
low-bypass engines and offered seating for 85 to 130 passengers. Launched in 1980 and introduced in 1984, the
737 Classic The Boeing 737 Classic is a series of narrow-body airliners produced by Boeing Commercial Airplanes, the second generation of the Boeing 737 series of aircraft. Development began in 1979 and the first variant, the 737-300, first flew in Februa ...
-300/400/500 variants were upgraded with CFM56-3 turbofans and offered 110 to 168 seats. Introduced in 1997, the
737 Next Generation The Boeing 737 Next Generation, commonly abbreviated as 737NG, or 737 Next Gen, is a narrow-body aircraft powered by two jet engines and produced by Boeing Commercial Airplanes. Launched in 1993 as the third generation derivative of the Boeing ...
(NG) -600/700/800/900 variants have updated CFM56-7s, a larger wing and an upgraded
glass cockpit A glass cockpit is an aircraft cockpit that features electronic (digital) flight instrument displays, typically large LCD screens, rather than the traditional style of analog dials and gauges. While a traditional cockpit relies on numerous ...
, and seat 108 to 215 passengers. The latest generation, the
737 MAX The Boeing 737 MAX is the fourth generation of the Boeing 737, a narrow-body airliner manufactured by Boeing Commercial Airplanes (BCA), a division of American company Boeing. It succeeds the Boeing 737 Next Generation (NG) and competes with th ...
, 737-7/8/9/10 MAX, powered by improved CFM LEAP-1B high bypass turbofans and accommodating 138 to 204 people, entered service in 2017.
Boeing Business Jet Boeing Business Jets (BBJ) are versions of Boeing's jet airliners with modifications to serve the private, head of state and corporate jet market. In 1996, Phil Condit, president of The Boeing Company, and Jack Welch, chairman and CEO of Genera ...
versions are produced since the 737NG, as well as military models. , 15,348 Boeing 737s have been ordered and 11,154 delivered. Initially, its main competitor was the
McDonnell Douglas DC-9 The McDonnell Douglas DC-9 is an American five-abreast single-aisle aircraft designed by the Douglas Aircraft Company. It was initially produced by the developer company as the Douglas DC-9 until August 1967 and then by McDonnell Douglas. Afte ...
, followed by its
MD-80 The McDonnell Douglas MD-80 is a series of five-abreast single-aisle airliners developed by McDonnell Douglas. It was produced by the developer company until August 1997 and then by Boeing Commercial Airplanes. The MD-80 was the second gene ...
/
MD-90 The McDonnell Douglas (later Boeing) MD-90 is an American five-abreast single-aisle airliner developed by McDonnell Douglas from its successful model MD-80. The airliner was produced by the developer company until 1997 and then by Boeing Comme ...
derivatives. In 2013, the global 737 fleet had completed more than 184 million flights over 264 million block hours since its entry into service. It was the highest-selling commercial aircraft until being surpassed by the competing
Airbus A320 family The Airbus A320 family is a series of Narrow-body aircraft, narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, Maiden flight, first flew on 22 February 1987, and was introduced in April 1988 by Air F ...
in October 2019, but maintains the record in total deliveries. The 737 MAX, designed to compete with the
A320neo The Airbus A320neo family is a development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' for "new engine option") is based on the previous A319, A320 and A321 ( enhanced variant), which was then ren ...
, was grounded worldwide between March 2019 and November 2020 following two fatal crashes.


Development


Initial design

Boeing had been studying short-haul jet aircraft designs, and saw a need for a new aircraft to supplement the 727 on short and thin routes.Transport News: Boeing Plans Jet.
" ''
The New York Times ''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid d ...
'', July 17, 1964. Retrieved: February 26, 2008.
Preliminary design work began on May 11, 1964, based on research that indicated a market for a fifty to sixty passenger airliner flying routes of . The initial concept featured
podded engine A podded engine is a jet engine that has been built up and integrated in its nacelle. This may be done in a podding facility as part of an aircraft assembly process. The nacelle contains the engine, engine mounts and parts which are required to r ...
s on the aft fuselage, a
T-tail A T-tail is an empennage configuration in which the tailplane is mounted to the top of the fin. The arrangement looks like the capital letter T, hence the name. The T-tail differs from the standard configuration in which the tailplane ...
as with the 727, and five-abreast seating. Engineer
Joe Sutter Joseph Frederick Sutter (March 21, 1921 – August 30, 2016) was an American engineer for the Boeing Airplane Company and manager of the design team for the Boeing 747 under Malcolm T. Stamper, the head of the 747 project. '' Air & Space/Sm ...
relocated the engines to the wings which lightened the structure and simplified the accommodation of six-abreast seating in the fuselage. The engine
nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached ...
s were mounted directly to the underside of the wings, without pylons, allowing the
landing gear Landing gear is the undercarriage of an aircraft or spacecraft that is used for takeoff or landing. For aircraft it is generally needed for both. It was also formerly called ''alighting gear'' by some manufacturers, such as the Glenn L. Martin ...
to be shortened, thus lowering the fuselage to improve baggage and passenger access. Relocating the engines from the aft fuselage also allowed the horizontal stabilizer to be attached to the aft fuselage instead of as a T-tail. Many designs for the engine attachment strut were tested in the wind tunnel and the optimal shape for high speed was found to be one which was relatively thick, filling the narrow channels formed between the wing and the top of the nacelle, particularly on the outboard side. At the time, Boeing was far behind its competitors; the SE 210 Caravelle had been in service since 1955, and the BAC One-Eleven (BAC-111),
Douglas DC-9 The McDonnell Douglas DC-9 is an American five-abreast single-aisle aircraft designed by the Douglas Aircraft Company. It was initially produced by the developer company as the Douglas DC-9 until August 1967 and then by McDonnell Douglas. After ...
, and
Fokker F28 The Fokker F28 Fellowship is a twin-engined, short-range jet airliner designed and built by Dutch aircraft manufacturer Fokker. Following the Fokker F27 Friendship, an early and commercially successful turboprop-powered regional airliner, Fokk ...
were already into flight certification. To expedite development, Boeing used 60% of the structure and systems of the existing 727, the most notable being the fuselage, which differs in length only. This 148-inch (3.76 m) wide fuselage cross-section permitted six-abreast seating compared to the rivals' five-abreast. The 727's fuselage was derived from the 707. The proposed wing airfoil sections were based on those of the 707 and 727, but somewhat thicker; altering these sections near the nacelles achieved a substantial drag reduction at high Mach numbers. The engine chosen was the Pratt & Whitney JT8D-1 low-bypass ratio turbofan engine, delivering of thrust. The concept design was presented in October 1964 at the
Air Transport Association Airlines for America (A4A), formerly known as Air Transport Association of America (ATA), is an American trade association and lobbying group based in Washington, D.C. that represents major North American airlines. Profile Mission A4A ...
maintenance and engineering conference by chief project engineer Jack Steiner, where its elaborate
high-lift device In aircraft design and aerospace engineering, a high-lift device is a component or mechanism on an aircraft's wing that increases the amount of lift produced by the wing. The device may be a fixed component, or a movable mechanism which is deplo ...
s raised concerns about
maintenance Maintenance may refer to: Biological science * Maintenance of an organism * Maintenance respiration Non-technical maintenance * Alimony, also called ''maintenance'' in British English * Champerty and maintenance, two related legal doct ...
costs and dispatch reliability.


Major design developments

The original 737 continued to be developed into thirteen passenger, cargo, corporate and military variants. These were later divided into what has become known as the four generations of the Boeing 737 family: * The first generation "Original" series: the 737-100 and -200, also the military T-43 and C-43, launched February 1965. * The second generation "Classic" series: 737-300, -400 and -500, launched in 1979. * The third generation "NG" series: 737-600, -700, -800 and -900, also the military C-40 and P-8, launched late 1993. * The fourth generation 737 MAX series: 737-7, -8, -9 and -10, launched August 2011.


Launch

The launch decision for the $150 million development was made by the board on February 1, 1965.
Lufthansa Deutsche Lufthansa AG (), commonly shortened to Lufthansa, is the flag carrier of Germany. When combined with its subsidiaries, it is the second- largest airline in Europe in terms of passengers carried. Lufthansa is one of the five founding ...
became the launch customer on February 19, 1965, with an order for 21 aircraft, worth $67 million"German Airline Buys 21 Boeing Short-Range Jets." ''
The Washington Post ''The Washington Post'' (also known as the ''Post'' and, informally, ''WaPo'') is an American daily newspaper published in Washington, D.C. It is the most widely circulated newspaper within the Washington metropolitan area and has a large nati ...
'', February 20, 1965. Retrieved: February 26, 2008.
after the airline had been assured by Boeing that the 737 project would not be canceled.Wallace, J
"Boeing delivers its 5,000th 737."
''Seattle Post-Intelligencer'', February 13, 2006. Retrieved June 7, 2011.
Consultation with Lufthansa over the previous winter had resulted in the seating capacity being increased to 100. On April 5, 1965, Boeing announced an order by
United Airlines United Airlines, Inc. (commonly referred to as United), is a major American airline headquartered at the Willis Tower in Chicago, Illinois.
for 40 737s. United wanted a slightly larger capacity than the 737-100, so the fuselage was stretched ahead of, and behind the wing. The longer version was designated the 737-200, with the original short-body aircraft becoming the 737-100. Detailed design work continued on both variants simultaneously.


Introduction

The first -100 was rolled out on January 17, 1967, and took its maiden flight on April 9, 1967, piloted by
Brien Wygle Brien Singleton Wygle (August 23, 1924 – September 15, 2020) was an American pilot from Seattle, Washington. Wygle was a test pilot for Boeing. Early life On August 23, 1924. Wygle was born as Brien Singleton Wygle in Seattle, Washington. Wy ...
and Lew Wallick. After several test flights the
Federal Aviation Administration The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic ...
(FAA) issued Type Certificate A16WE certifying the 737-100 for commercial flight on December 15, 1967."Type Certificate Data Sheet A16WE."
''faa.gov.'' Retrieved: September 3, 2010.
It was the first aircraft to have, as part of its initial certification, approval for Category II approaches, which refers to a precision instrument approach and landing with a decision height between . Lufthansa received its first aircraft on December 28, 1967, and on February 10, 1968, became the first non-American airline to launch a new Boeing aircraft. Lufthansa was the only significant customer to purchase the 737-100 and only 30 aircraft were produced. The -200 was rolled out on June 29, 1967, and had its maiden flight on August 8, 1967. It was then certified by the FAA on December 21, 1967. The inaugural flight for United Airlines took place on April 28, 1968, from
Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ...
to
Grand Rapids, Michigan Grand Rapids is a city and county seat of Kent County in the U.S. state of Michigan. At the 2020 census, the city had a population of 198,917 which ranks it as the second most-populated city in the state after Detroit. Grand Rapids is the ...
. The lengthened -200 was widely preferred over the -100 by airlines. The improved version, the 737-200 Advanced, was introduced into service by
All Nippon Airways , also known as ANA (''Ē-enu-ē'') or is an airline in Japan. Its headquarters are located in Shiodome City Center in the Shiodome area of Minato ward of Tokyo. It operates services to both domestic and international destinations and had m ...
on May 20, 1971. The 737 original model with its variants, known later as the ''Boeing 737 Original'', initially competed with SE 210 Caravelle and BAC-111 due to their earlier entry into service and later primarily with the
McDonnell Douglas McDonnell Douglas was a major American aerospace manufacturing corporation and defense contractor, formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own merger with Boeing in 1997, it pro ...
DC-9, then its
MD-80 The McDonnell Douglas MD-80 is a series of five-abreast single-aisle airliners developed by McDonnell Douglas. It was produced by the developer company until August 1997 and then by Boeing Commercial Airplanes. The MD-80 was the second gene ...
derivatives as the three European short-haul single aisles slowly withdrew from the competition. Sales were low in the early 1970s and, after a peak of 114 deliveries in 1969, only 22 737s were shipped in 1972 with 19 in backlog. The
US Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Sig ...
saved the program by ordering T-43s, which were modified Boeing 737-200s. African airline orders kept the production running until the 1978 US
Airline Deregulation Act The Airline Deregulation Act is a 1978 United States federal law that deregulated the airline industry in the United States, removing federal control over such areas as fares, routes, and market entry of new airlines. The Civil Aeronautics Boa ...
, which improved demand for six-abreast narrow-body aircraft. Demand further increased after being re-engined with the
CFM56 The CFM International CFM56 (U.S. military designation F108) series is a Franco-American family of high-bypass turbofan aircraft engines made by CFM International (CFMI), with a thrust range of . CFMI is a 50–50 joint-owned company of Safran ...
. The 737 went on to become the highest-selling commercial aircraft until surpassed by the competing
Airbus A320 family The Airbus A320 family is a series of Narrow-body aircraft, narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, Maiden flight, first flew on 22 February 1987, and was introduced in April 1988 by Air F ...
in October 2019, but maintains the record in total deliveries. The fuselage is manufactured in
Wichita, Kansas Wichita ( ) is the largest city in the U.S. state of Kansas and the county seat of Sedgwick County. As of the 2020 census, the population of the city was 397,532. The Wichita metro area had a population of 647,610 in 2020. It is located in ...
, by Boeing spin-off company
Spirit AeroSystems Spirit AeroSystems Holdings, Inc., based in Wichita, Kansas, is the world's largest first-tier aerostructures manufacturer. The company builds several important pieces of Boeing aircraft, including the fuselage of the 737, portions of the 787 fu ...
, before being moved by rail to Renton.


Generations and variants


737 Original (first generation)

The ''Boeing 737 Original'' is the name given to the -100/200 and -200 Advanced series of the Boeing 737 family.


737-100

The initial model was the 737-100, the smallest variant of the 737 aircraft family, which was launched in February 1965 and entered service with
Lufthansa Deutsche Lufthansa AG (), commonly shortened to Lufthansa, is the flag carrier of Germany. When combined with its subsidiaries, it is the second- largest airline in Europe in terms of passengers carried. Lufthansa is one of the five founding ...
in February 1968. In 1968, its unit cost was
US$ The United States dollar (symbol: $; code: USD; also abbreviated US$ or U.S. Dollar, to distinguish it from other dollar-denominated currencies; referred to as the dollar, U.S. dollar, American dollar, or colloquially buck) is the official ...
3.7M (1968), $M today. A total of 30 737-100s were ordered: 22 by Lufthansa, 5 by Malaysia–Singapore Airlines (MSA) and 2 by
Avianca Avianca S.A. ( acronym in Spanish for ''Aerovias del Continente Americano S.A.'', "Airways of the American Continent") is a Colombian airline. It has been the flag carrier of Colombia since December 5, 1919, when it was initially registered und ...
with the final commercial aircraft delivered to MSA on October 31, 1969. The first aircraft used by Boeing as prototype under registration N73700 was later ordered by and delivered to
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
on July 26, 1973, which then operated it under registration N515NA and retired after 30 years on September 27, 2003. This was the last operated 737-100 and is the only remaining worldwide, which is on the static display in the
Museum of Flight The Museum of Flight is a private non-profit air and space museum in the Seattle metropolitan area. It is located at the southern end of King County International Airport (Boeing Field) in the city of Tukwila, immediately south of Seattle. ...
in
Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...
. The original engine nacelles incorporated thrust reversers taken from the 727 outboard nacelles. They proved to be relatively ineffective and tended to lift the aircraft up off the runway when deployed. This reduced the downforce on the main wheels thereby reducing the effectiveness of the wheel brakes. In 1968, an improvement to the
thrust reversal Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's thrust for it to act against the forward travel of the aircraft, providing deceleration. Thrust reverser systems are featured on many jet aircraft t ...
system was introduced. A 48-inch tailpipe extension was added and new target-style thrust reversers were incorporated. The thrust reverser doors were set 35 degrees away from the vertical to allow the exhaust to be deflected inboard and over the wings and outboard and under the wings. The improvement became standard on all aircraft after March 1969, and a retrofit was provided for active aircraft. Longer nacelle/wing fairings were introduced, and the airflow over the flaps and slats was improved. The production line also introduced an improvement to the flap system, allowing increased use during takeoff and landing. All these changes gave the aircraft a boost to payload and range, and improved short-field performance.


737-200

The 737-200 was a 737-100 with an extended fuselage, launched by an order from United Airlines in 1965 and entered service with the launch customer in April 1968. Its unit cost was US$4.0M (1968) ($M today). The -200's unit cost was US$5.2M (1972) ($M today). The 737-200 Advanced is an improved version of the -200, introduced into service by
All Nippon Airways , also known as ANA (''Ē-enu-ē'') or is an airline in Japan. Its headquarters are located in Shiodome City Center in the Shiodome area of Minato ward of Tokyo. It operates services to both domestic and international destinations and had m ...
on May 20, 1971. After aircraft #135, the 737-200 Advanced has improved aerodynamics, automatic wheel brakes, more powerful engines, more fuel capacity, and hence a 15% increase in payload and range over the original -200s and respectively -100s. The 737-200 Advanced became the production standard in June 1971. Boeing also provided the 737-200C ( Combi), which allowed for conversion between passenger and cargo use and the 737-200QC (Quick Change), which facilitated a rapid conversion between roles. The 1,095th and last delivery of a -200 series aircraft was in August 1988 to
Xiamen Airlines XiamenAir, also known as Xiamen Airlines, is a Chinese passenger airline based in Xiamen, Fujian Province. The airline operates scheduled passenger flights out of Xiamen Gaoqi International Airport and, to a lesser extent, Beijing Daxing Interna ...
."About the 737 Family."
''The Boeing Company''. Retrieved: December 20, 2007.
Nineteen 737-200s, designated T-43, were used to train aircraft navigators for the
U.S. Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Sign ...
. Some were modified into CT-43s, which are used to transport passengers, and one was modified as the NT-43A Radar Test Bed. The first was delivered on July 31, 1973, and the last on July 19, 1974. The
Indonesian Air Force The Indonesian Air Force ( id, Tentara Nasional Indonesia Angkatan Udara (TNI-AU), literally "''Indonesian National Military-Air Force''") sometimes shortened as IDAF / IdAF, is the aerial branch of the Indonesian National Armed Forces. The I ...
ordered three modified 737-200s, designated ''Boeing 737-2x9 Surveiller''. They were used as Maritime reconnaissance (MPA)/transport aircraft, fitted with SLAMMAR (Side-looking Multi-mission Airborne Radar). The aircraft were delivered between May 1982 and October 1983. Delta Express promoted the Cartoon Network animated television series ''
The Powerpuff Girls ''The Powerpuff Girls'' is an American superhero animated television series created by animator Craig McCracken and produced by Hanna-Barbera (later Cartoon Network Studios) for Cartoon Network and distributed by Warner Bros. Domestic Telev ...
'' by having a 737-200 painted with a special livery featuring the characters Blossom, Bubbles, and Buttercup on the exterior. The plane's inaugural flight was held at
Logan International Airport General Edward Lawrence Logan International Airport , also known as Boston Logan International Airport and commonly as Boston Logan, Logan Airport or simply Logan, is an international airport that is located mostly in East Boston and partial ...
in Boston, Massachusetts, on July 17, 2000. In 2002, the aircraft was repainted with a different ''Powerpuff Girls'' theme to promote ''
The Powerpuff Girls Movie ''The Powerpuff Girls Movie'' is a 2002 American animated superhero film based on the Cartoon Network animated television series ''The Powerpuff Girls''. It was co-written and directed by series' creator Craig McCracken (in his directorial debu ...
''. After 40 years, in March 2008, the final 737-200 aircraft in the U.S. flying scheduled passenger service were phased out, with the last flights of
Aloha Airlines Aloha Airlines was an American airline headquartered in Honolulu, Hawaii, operating from a hub at Honolulu International Airport (now Daniel K. Inouye International Airport). Operations began on July 26, 1946, and ceased operations on March 3 ...
. As of 2018, the variant still saw regular service through North American charter operators such as
Sierra Pacific Airlines Sierra Pacific Airlines is an American charter airline based in Tucson, Arizona, USA. It operates passenger charters and sub-charters for other airlines, as well as for the United States Forest Service, United States Military and the United Sta ...
. With the improved short-field capabilities of the 737-200, Boeing offered the option of the gravel kit modification features preventing
foreign object damage In aviation and aerospace, foreign object debris (FOD), is any particle or substance, alien to an aircraft or system, which could potentially cause damage. External FOD hazards include bird strikes, hail, ice, sandstorms, ash-clouds or obje ...
, which enables this aircraft to operate on remote, unimproved or unpaved runways, such as gravel runways, that other similarly sized jetliners cannot. Until retiring its -200 fleet in 2007,
Alaska Airlines Alaska Airlines is a major American airline headquartered in SeaTac, Washington, within the Seattle metropolitan area. It is the sixth largest airline in North America when measured by fleet size, scheduled passengers carried, and the num ...
used this option for some of its
combi aircraft Combi aircraft in commercial aviation are aircraft that can be used to carry either passengers as an airliner, or cargo as a freighter, and may have a partition in the aircraft cabin to allow both uses at the same time in a mixed passenger/fre ...
rural operations to serve many unimproved runways in
Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...
. Gravel-kitted 737-200 Combis are still used by
Canadian North Bradley Air Services, operating as Canadian North, is a wholly Inuit-owned airline headquartered in Kanata, Ontario, Canada. It operates scheduled passenger services to communities in the Northwest Territories, Nunavut and the Nunavik region ...
(which is due to retire their last one in early 2023),
Air Inuit Air Inuit ( Inuktitut syllabics: ᐃᓄᐃᑦ ᖃᖓᑦᑕᔪᖏᑦ) is an airline based in the Montreal borough of Saint-Laurent, Quebec, Canada. It operates domestic passenger services and charter and cargo services in Nunavik, Labrador a ...
,
Nolinor Aviation Les Investissements Nolinor Inc., trading as Nolinor Aviation, is a charter airline based in Mirabel, a suburb of Montreal, Quebec, Canada. It operates passenger charter and cargo services within Canada and to the U.S. Its main base is Montré ...
and
Chrono Aviation Chrono Aviation Inc., and its wholly owned subsidiary Chrono Jet Inc., is a charter airline headquartered at Québec City Jean Lesage International Airport. It operates aircraft in passenger (9 to 120), cargo and combi roles. It has bases at Mon ...
in Northern Canada where gravel runways are common. In July 2019, there were 46 Boeing 737-200s in service, mostly with "second and third tier" airlines, and those of developing nations.


737 Classic (second generation)

The ''Boeing 737 Classic'' is the name given to the 737-300/400/500 series after the introduction of the -600/700/800/900 series of the Boeing 737 family. Produced from 1984 to 2000, a total of 1,988 Classic series were delivered. Close to the next major upgrade of single aisle aircraft at Airbus and Boeing, the price of jet fuel reached a peak in 2008, when airlines devoted 40% of the retail price of an air ticket to pay for fuel, versus 15% in 2000. Consequently, in that year carriers retired Boeing 737 Classic aircraft to reduce fuel consumption; replacements consisted of more efficient 737 Next Generation or A320 family aircraft. On June 4, 2008,
United Airlines United Airlines, Inc. (commonly referred to as United), is a major American airline headquartered at the Willis Tower in Chicago, Illinois.
announced it would retire all 94 of its Classic 737 aircraft (64 737-300 and 30 737-500 aircraft), replacing them with A320 family jets taken from its
Ted TED may refer to: Economics and finance * TED spread between U.S. Treasuries and Eurodollar Education * ''Türk Eğitim Derneği'', the Turkish Education Association ** TED Ankara College Foundation Schools, Turkey ** Transvaal Education Depa ...
subsidiary, which has been shut down. This intensified the competition between the two giant aircraft manufacturers, which has since become a duopoly competition. An optional upgrade with winglets became available for the Classic and NG series. * The 737-300 can be retrofitted with
Aviation Partners Aviation Partners Inc. (API) is a Seattle-based private corporation that specializes in performance-enhancing winglet systems. The corporation was founded in 1991 and is owned by The Washington Companies. History API was founded in 1991 by Joe Cl ...
Boeing winglets. The 737-300 retrofitted with winglets is designated the -300SP (Special Performance). * WestJet was to launch the 737-600 with winglets, but dropped them in 2006.


737-300

Development began in 1979 for the 737's first major revision, which was originally introduced as the 'new generation' of the 737. Boeing wanted to increase capacity and range, incorporating improvements to upgrade the aircraft to modern specifications, while also retaining commonality with previous 737 variants. In 1980, preliminary aircraft specifications of the variant, dubbed 737-300, were released at the
Farnborough Airshow The Farnborough Airshow, officially the Farnborough International Airshow, is a trade exhibition for the aerospace and defence industries, where civilian and military aircraft are demonstrated to potential customers and investors. Since its fir ...
. This first major upgrade series was later renamed to the 737 Classic series. It competed primarily with MD-80, its later derivative
MD-90 The McDonnell Douglas (later Boeing) MD-90 is an American five-abreast single-aisle airliner developed by McDonnell Douglas from its successful model MD-80. The airliner was produced by the developer company until 1997 and then by Boeing Comme ...
and the newcomer
Airbus A320 family The Airbus A320 family is a series of Narrow-body aircraft, narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, Maiden flight, first flew on 22 February 1987, and was introduced in April 1988 by Air F ...
. Boeing engineer Mark Gregoire led a design team, which cooperated with
CFM International CFM International is a 50/50 Franco-American joint venture between GE Aviation and Safran Aircraft Engines (formerly known as Snecma). It was formed to build and support the CFM56 series of turbofan engines. The company is the world’s lead ...
to select, modify and deploy a new engine and nacelle that would make the 737-300 into a viable aircraft. They chose the CFM56-3B-1 high-bypass
turbofan The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which ac ...
engine to power the aircraft, which yielded significant gains in fuel economy and a reduction in noise, but also posed an engineering challenge, given the low ground clearance of the 737 and the larger diameter of the engine over the original Pratt & Whitney engines. Gregoire's team and CFM solved the problem by reducing the size of the fan (which made the engine slightly less efficient than it had been forecast to be), placing the engine ahead of the wing, and by moving engine accessories to the sides of the engine pod, giving the engine a distinctive non-circular "hamster pouch" air intake. Earlier customers for the CFM56 included the U.S. Air Force with its program to re-engine KC-135 tankers. The passenger capacity of the aircraft was increased to 149 by extending the fuselage around the wing by . The wing incorporated several changes for improved aerodynamics. The wingtip was extended , and the wingspan by . The leading-edge slats and trailing-edge flaps were adjusted. The tailfin was redesigned, the flight deck was improved with the optional EFIS (Electronic Flight Instrumentation System), and the passenger cabin incorporated improvements similar to those developed on the
Boeing 757 The Boeing 757 is an American narrow-body airliner designed and built by Boeing Commercial Airplanes. The then-named 7N7, a twinjet successor for the 727 (a trijet), received its first orders in August 1978. The prototype completed its mai ...
. The prototype -300, the 1,001st 737 built, first flew on February 24, 1984, with pilot Jim McRoberts. It and two production aircraft flew a nine-month-long certification program. The 737-300 retrofitted with
Aviation Partners Aviation Partners Inc. (API) is a Seattle-based private corporation that specializes in performance-enhancing winglet systems. The corporation was founded in 1991 and is owned by The Washington Companies. History API was founded in 1991 by Joe Cl ...
' winglets was designated the -300SP (''Special Performance''). The 737-300 was replaced by the 737-700 of the Next Generation series.


737-400

The 737-400 was launched in 1985 to fill the gap between the 737-300 and the 757-200. In June 1986, Boeing announced the development of the 737-400, which stretched the fuselage a further , increasing the capacity to 188 passengers, and requiring a tail bumper to prevent
tailstrike In aviation, a tailstrike or tail strike occurs when the tail or empennage of an aircraft strikes the ground or other stationary object. This can happen with a fixed-wing aircraft with tricycle undercarriage, in both takeoff where the pilot rot ...
s during take-off and a strengthened
wing spar In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles (or thereabouts depending on wing sweep) to the fuselage. The spar carries flight loads and the weight of the wings while on t ...
. The -400s first flight was on February 19, 1988, and, after a seven-month/500-hour flight-testing run, entered service with
Piedmont Airlines Piedmont Airlines, Inc. is an American regional airline headquartered at the Salisbury Regional Airport in unincorporated Wicomico County, Maryland, near the city of Salisbury. The airline is a wholly-owned subsidiary of the American Airline ...
that October. The last two -400s, i.e. the last 737 Classics series, were delivered to
CSA Czech Airlines Czech Airlines j.s.c. (abbreviation: ČSA, cz, České Aerolinie, a.s.) is the flag carrier of the Czech Republic. Its head office is located in the Vokovice area of Prague's 6th district and its hub is Václav Havel Airport Prague. The comp ...
on February 28, 2000. The 737-400 was replaced by the 737-800 of the Next Generation series. The 737-400SF was a 737-400 converted to freighter, though it was not a model delivered by Boeing and hence the nickname ''Special Freighter (SF)''.
Alaska Airlines Alaska Airlines is a major American airline headquartered in SeaTac, Washington, within the Seattle metropolitan area. It is the sixth largest airline in North America when measured by fleet size, scheduled passengers carried, and the num ...
was the first to convert one of their 400s from regular service to an aircraft with the ability to handle 10 pallets. The airline had also converted five more into fixed combi aircraft for half passenger and freight. These 737-400 Combi aircraft were retired in 2017 and replaced by the 737-700F of the Next Generation series.


737-500

The 737-500 was offered as a modern and direct replacement of the 737-200. It was launched in 1987 by Southwest Airlines, with an order for 20 aircraft, and it flew for the first time on June 30, 1989. A single prototype flew 375 hours for the certification process, and on February 28, 1990, Southwest Airlines received the first delivery. The -500 incorporated the improvements of the 737 Classic series, allowing longer routes with fewer passengers to be more economical than with the 737-300. The fuselage length of the 737-500 is longer than the 737-200, accommodating up to 140 passengers. Both glass and older-style mechanical cockpits arrangements were available. Using the CFM56-3 engine also gave a 25% increase in fuel efficiency over the older 737-200s P&W engines. The 737-500 has faced accelerated retirement due to its smaller size, after 21 years in service compared to 24 years for the -300. While a few 737-300s were slated for freighter conversion, no demand at all existed for a -500 freighter conversion. The 737-500 was replaced by the 737-600 of the Next Generation series, though the -600 was not as successful in total orders as the -500.


737 NG (third generation)

The ''Boeing 737 Next Generation'', abbreviated as ''737 Next Gen'' or ''737NG'', is the name given to the main models 737-600/700/800/900 series and the extended range -700ER/900ER variants of the Boeing 737 family. It has been produced since 1996 and introduced in 1997, with a total order of 7,097 aircraft, of which 7,031 have been delivered . The main development was to re-engine with the high pressure ratio CFM56-7. By the early 1990s, while the MD-80 slowly withdraw from the competition leading to introduction of the MD-90, it had become clear that the new A320 family was a serious threat to Boeing's market share, as Airbus won previously loyal 737 customers such as Lufthansa and United Airlines. In November 1993, to keep the hand in the single aisle competition, Boeing's board of directors authorized the Next Generation program to mainly upgrade the
737 Classic The Boeing 737 Classic is a series of narrow-body airliners produced by Boeing Commercial Airplanes, the second generation of the Boeing 737 series of aircraft. Development began in 1979 and the first variant, the 737-300, first flew in Februa ...
series. In late 1993, after engineering trade studies and discussions with major customers, Boeing proceeded to launch a second derivative of the Boeing 737, the
737 Next Generation The Boeing 737 Next Generation, commonly abbreviated as 737NG, or 737 Next Gen, is a narrow-body aircraft powered by two jet engines and produced by Boeing Commercial Airplanes. Launched in 1993 as the third generation derivative of the Boeing ...
(NG) -600/700/800/900 series. It featured a redesigned wing with a wider wingspan and larger area, greater fuel capacity, longer range and higher
MTOW The maximum takeoff weight (MTOW) or maximum gross takeoff weight (MGTOW) or maximum takeoff mass (MTOM) of an aircraft is the maximum weight at which the pilot is allowed to attempt to take off, due to structural or other limits. The analogous ...
s. It was equipped with CFM56-7 high pressure ratio engines, a
glass cockpit A glass cockpit is an aircraft cockpit that features electronic (digital) flight instrument displays, typically large LCD screens, rather than the traditional style of analog dials and gauges. While a traditional cockpit relies on numerous ...
, and upgraded interior configurations. The four main models of the series can accommodate seating for 108 to 215 passengers. It was further developed into additional versions such as the corporate
Boeing Business Jet Boeing Business Jets (BBJ) are versions of Boeing's jet airliners with modifications to serve the private, head of state and corporate jet market. In 1996, Phil Condit, president of The Boeing Company, and Jack Welch, chairman and CEO of Genera ...
(BBJ) and military
P-8 Poseidon The Boeing P-8 Poseidon is an American maritime patrol and reconnaissance aircraft developed and produced by Boeing Defense, Space & Security, and derived from the civilian Boeing 737-800. It was developed for the United States Navy (USN). Th ...
aircraft. Following the merger between Boeing with McDonnell Douglas in 1997, the primary competitor for the 737NG series remained only the A320 family.


737-600

The 737-600, the smallest model of the Next-Generation, was launched by Scandinavian Airlines (SAS) in March 1995 with the first aircraft delivered in September 1998. A total of 69 aircraft without
winglets Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft' ...
have been produced with the last one delivered to
WestJet WestJet Airlines Ltd. is a Canadian airline headquartered in Calgary, Alberta, near Calgary International Airport. It is the second-largest Canadian airline, behind Air Canada, operating an average of 777 flights and carrying more than 66,130 ...
in 2006. The 737-600 replaced the 737-500 and is similar to the Airbus A318.


737-700

The 737-700, the first variant of the Next-Generation, was launched in November 1993 with an order of 63 aircraft. The -700 seats 126 passengers in a two-class or 149 passengers in a one-class layout. The launch customer Southwest Airlines took the first delivery in December 1997. The 737-700 replaced the 737-300 and competes with the
Airbus A319 The Airbus A319 is a member of the Airbus A320 family of short- to medium-range, narrow-body, commercial passenger twin-engine jet airliners manufactured by Airbus. The A319 carries 124 to 156 passengers and has a maximum range of . Final assem ...
. The ''737-700C'' is a convertible version where the seats can be removed to carry cargo instead. There is a large door on the left side of the aircraft. The
United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
was the launch customer for the 737-700C under the military designation
C-40 Clipper The Boeing C-40 Clipper is a military version of the Boeing 737 Next Generation used to transport cargo and passengers. It is used by the United States Navy, Air Force, and Marine Corps. The Navy C-40A variant is named "Clipper", whereas the ...
. The ''737-700ER'' (Extended
Range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...
) was launched on January 31, 2006, and featured the fuselage of the 737-700 and the wings and landing gear of the 737-800. A 737-700ER can typically accommodate 126 passengers in two classes with a range similar to the Airbus A319LR.


737-800

The Boeing 737-800 was a stretched version of the 737-700 launched on September 5, 1994. The -800 seats 162 passengers in a two-class or 189 passengers in a high-density, one-class layout. Launch customer
Hapag-Lloyd Flug Hapag-Lloyd Flug (between 2005 and 2007 also marketed as ''Hapagfly'') was a German leisure airline headquartered in Langenhagen, Lower Saxony that was originally founded by Hapag-Lloyd and later became a subsidiary of TUI Group. It operated sch ...
(now
TUIfly TUI fly Deutschland, formerly ''TUIfly'', is a German leisure airline owned by the travel and tourism company TUI Group. It is headquartered at Hannover Airport with bases at several other German airports. TUI fly Deutschland is part of TUI Gr ...
) received the first one in April 1998. The -800 replaced directly the -400 and aging 727-200 of US airlines. It filled also the gap left by Boeing's decision to discontinue the MD-80 and
MD-90 The McDonnell Douglas (later Boeing) MD-90 is an American five-abreast single-aisle airliner developed by McDonnell Douglas from its successful model MD-80. The airliner was produced by the developer company until 1997 and then by Boeing Comme ...
aircraft, following Boeing's merger with McDonnell Douglas. The 737-800 is the most widely used narrowbody aircraft and competes primarily with the Airbus A320.


737-900

The 737-900 was launched in 1997 and took its first flight on August 3, 2000. It retains the
MTOW The maximum takeoff weight (MTOW) or maximum gross takeoff weight (MGTOW) or maximum takeoff mass (MTOM) of an aircraft is the maximum weight at which the pilot is allowed to attempt to take off, due to structural or other limits. The analogous ...
, fuel capacity, trading range for payload and also the exit configuration of the -800, limiting its seat capacity to approximately 177 in a two class and 189 in a high-density, one class layout. The launch customer
Alaska Airlines Alaska Airlines is a major American airline headquartered in SeaTac, Washington, within the Seattle metropolitan area. It is the sixth largest airline in North America when measured by fleet size, scheduled passengers carried, and the num ...
received the delivery on May 15, 2001. The ''737-900ER'' (Extended Range) is the newest and largest variant of the 737NG generation. An additional pair of exit doors and a flat
rear pressure bulkhead The aft pressure bulkhead or rear pressure bulkhead is the rear component of the pressure seal in all aircraft that cruise in a tropopause zone in the earth's atmosphere. It helps maintain pressure when stratocruising and protects the aircraft fro ...
increased its seating capacity to 180 passengers in a two-class and up to 220 passengers in a one-class configuration. The -900ER was introduced to meet the range and passenger capacity of the discontinued 757-200 and to directly compete with the Airbus A321.


737 MAX (fourth generation)

The ''Boeing 737 MAX'' is the name given to the main MAX 737-7/8/9/10 series and high-density MAX 200 variant of the Boeing 737 family. It is offered in four main variants, typically offering 138 to 230 seats and a range of . The 737 MAX 7, MAX 8 (including the denser, 200-seat MAX 200), and MAX 9 replace the 737-700, -800, and -900 respectively. The further stretched 737 MAX 10 has also been added to the series. The main development was to re-engine with CFM LEAP-1B very high bypass ratio. On July 20, 2011, Boeing announced plans for a third major upgrade and respectively fourth generation of 737 series to be powered by the CFM LEAP-1B engine, with
American Airlines American Airlines is a major airlines of the United States, major US-based airline headquartered in Fort Worth, Texas, within the Dallas–Fort Worth metroplex. It is the Largest airlines in the world, largest airline in the world when measured ...
intending to order 100 of these aircraft. On August 30, 2011, Boeing confirmed the launch of the 737 new engine variant, to be called the
Boeing 737 MAX The Boeing 737 MAX is the fourth generation of the Boeing 737, a narrow-body airliner manufactured by Boeing Commercial Airplanes (BCA), a division of American company Boeing. It succeeds the Boeing 737 Next Generation (NG) and competes with ...
. It was based on earlier 737 designs with more efficient LEAP-1B power plants, aerodynamic improvements (most notably split-tip
winglets Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft' ...
), and airframe modifications. It competes with the
Airbus A320neo family The Airbus A320neo family is a development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' for "new engine option") is based on the previous A319, A320 and A321 ( enhanced variant), which was then ren ...
that was launched in December 2010 and reached 1,029 orders by June 2011, breaking Boeing's monopoly with
American Airlines American Airlines is a major airlines of the United States, major US-based airline headquartered in Fort Worth, Texas, within the Dallas–Fort Worth metroplex. It is the Largest airlines in the world, largest airline in the world when measured ...
, which had an order for 130 A320neos that July. The 737 MAX had its first flight on January 29, 2016, and gained FAA certification on March 8, 2017. The first delivery was a MAX 8 on May 6, 2017, to
Lion Air PT Lion Mentari Airlines, operating as Lion Air, is an Indonesian low-cost airline. Based in Jakarta, Lion Air is the country's largest privately run airline, the second largest low-cost airline in Southeast Asia (after AirAsia) and the large ...
's subsidiary
Malindo Air Batik Air Malaysia (formerly known as Malindo Air) is a Malaysian full service carrier, an associate carrier of Indonesian Lion Air Group, with headquarters in Petaling Jaya, Selangor, Malaysia. The original name Malindo signifies a cooperative ...
, which put it into service on May 22, 2017. , the series has received 5,011 firm orders. In March 2019, civil aviation authorities around the world grounded the 737 MAX following two
hull loss A hull loss is an aviation accident that catastrophically damages the aircraft beyond economical repair, resulting in a total loss. The term also applies to situations in which the aircraft is missing, the search for their wreckage is terminate ...
crashes which caused 346 deaths. On December 16, 2019, Boeing announced that it would suspend production of the 737 MAX from January 2020, which was resumed in May 2020. In the midyear 2020, the FAA and Boeing conducted a series of recertification test flights. On November 18, 2020, the FAA cleared the MAX to return to service. Before the aircraft can fly again, repairs must be implemented and airlines' training programs must be approved. Passenger flights in the U.S. are expected to resume before the end of the year. Worldwide, the first airline to resume passenger service was Brazilian low-cost Gol, on December 9, 2020.


737 MAX 7

The 737 MAX 7, a shortened variant of the MAX 8, was originally based on the 737-700, flying farther and accommodating two more seat rows at 18% lower fuel costs per seat. The redesign uses the 737-8 wing and landing gear; a pair of over-wing exits rather than the single-door configuration; a aft fuselage and a longer forward fuselage; structural re-gauging and strengthening; and systems and interior modifications to accommodate the longer length. Entry into service with launch operator Southwest Airlines was expected in January 2019, but the airline deferred these orders until 2023–2024. The 737 MAX 7 replaced the 737-700 and was predicted to carry 12 more passengers and fly farther than
Airbus A319neo The Airbus A320neo family is a development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' for "new engine option") is based on the previous A319, A320 and A321 ( enhanced variant), which was then ren ...
with 7% lower operating costs per seat.


737 MAX 8

The MAX 8, the first variant of the 737 MAX, has a longer fuselage than the MAX 7. On July 23, 2013, Boeing completed the firm configuration for the 737 MAX 8. Its first commercial flight was operated by
Malindo Air Batik Air Malaysia (formerly known as Malindo Air) is a Malaysian full service carrier, an associate carrier of Indonesian Lion Air Group, with headquarters in Petaling Jaya, Selangor, Malaysia. The original name Malindo signifies a cooperative ...
on May 22, 2017. The MAX 8 replaced the 737-800 and competed with the A320neo. The 737 MAX 200, a high-density version of the 737 MAX 8, was launched in September 2014 and named for seating for up to 200 passengers in a single-class layout with slimline seats requiring an extra pair of exit doors. The MAX 200 would be 20% more cost-efficient per seat, including 5% lower operating costs than the MAX 8 and would be the most efficient narrow-body on the market when entering service. In mid-November 2018, the first MAX 200 of the 135 ordered by Ryanair rolled out, in a 197-seat configuration. It was first flown from Renton on January 13, 2019, and was due to enter service in April 2019.


737 MAX 9

The 737 MAX 9, the stretched variant of the MAX 8, was launched with an order of 201 aircraft in February 2012. It made its roll-out on March 7, 2017, and first flight on April 13, 2017; It was certified by February 2018. The launch customer, Lion Air Group, took the first MAX 9 on March 21, 2018, before entering service with
Thai Lion Air Thai Lion Mentari Co. Ltd, trading as Thai Lion Air ( th, ไทยไลอ้อนแอร์), is a Thai low-cost airline, operating with Thai partners as an associate company of Lion Air of Indonesia. The carrier operates from Bangkok's Do ...
. The 737 MAX 9 replaced the 737-900 and competes with the
Airbus A321neo The Airbus A320neo family is a development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' for "new engine option") is based on the previous A319, A320 and A321 ( enhanced variant), which was then ren ...
.


737 MAX 10

The MAX 10 was proposed as a stretched MAX 9 in mid-2016, enabling seating for 230 in a single class or 189 in two-class layout, compared to 193 in two-class seating for the A321neo. The modest stretch of fuselage enables the MAX 10 to retain the existing wing and CFM Leap 1B engine from the MAX 9 with a trailing-link main landing gear as the only major change. The MAX 10 was launched on June 19, 2017, with 240 orders and commitments from more than ten customers. The variant configuration with a predicted 5% lower trip cost and seat cost compared to the A321neo was firmed up by February 2018, and by mid-2018, the
critical design review In the United States military integrated acquisition lifecycle the Technical section has multiple acquisition "Technical Reviews". Technical reviews and audits assist the acquisition and the number and types are tailored to the acquisition. Over ...
was completed. The MAX 10 has a similar capacity to the A321XLR, but shorter range and much poorer field performance in smaller airports. It was unveiled in Boeing's Renton factory on November 22, 2019, and scheduled for first flight in 2020. Boeing also considered parallel development with the 757 replacement, similar to the development of the 757 and 767 in the 1970s. In the late 2010s, Boeing worked on a medium-range
Boeing New Midsize Airplane The New Midsize Airplane (NMA), or New Midsize Aircraft, (culturally referred to as the Boeing 797) is a concept airliner proposed by Boeing to fill the middle of the market segment. In 2015, Boeing determined the market was large enough to la ...
(NMA) with two variants seating 225 or 275 passengers and targeting the same market segment as the 737 MAX 10 and the Airbus A321neo. A Future Small Airplane (FSA) was also touted during this period. The NMA project was set aside in January 2020, as Boeing focused on returning the 737 MAX to service and announced that it would be taking a new approach to future projects.


Design

The 737 continued to evolve into many variants but still remains recognisable as the 737. These are divided into four generations but all are based on the same basic design.


Airframe

The fuselage cross section and nose are derived from that of the Boeing 707 and
Boeing 727 The Boeing 727 is an American narrow-body airliner that was developed and produced by Boeing Commercial Airplanes. After the heavy 707 quad-jet was introduced in 1958, Boeing addressed the demand for shorter flight lengths from smaller air ...
. Early 737 cockpits also inherited the "eyebrow windows" positioned above the main glareshield, which were a feature of the original 707 and 727 to allow for better crew visibility. Contrary to popular belief, these windows were not intended for celestial navigation (only the military T-43A had a sextant port for star navigation, which the civilian models lacked.) With modern avionics, the windows became redundant, and many pilots placed newspapers or other objects in them to block out sun glare. They were eliminated from the 737 cockpit design in 2004, although they are still installed on customer request. The eyebrow windows were sometimes removed and plugged, usually during maintenance overhauls, and can be distinguished by the metal plug which differs from the smooth metal in later aircraft that were not originally fitted with the windows. The 737's main landing gear, under the wings at mid-cabin, rotates into wheel wells in the aircraft's belly. The legs are covered by partial doors, and "brush-like" seals aerodynamically smooth (or "fair") the wheels in the wells. The sides of the tires are exposed to the air in flight. "Hub caps" complete the aerodynamic profile of the wheels. It is forbidden to operate without the caps, because they are linked to the ground speed sensor that interfaces with the anti-skid brake system. The dark circles of the tires are clearly visible when a 737 takes off, or is at low altitude. From July 2008, the steel landing gear brakes on new NGs were replaced by Messier-Bugatti carbon brakes, achieving weight savings to depending on whether standard or high-capacity brakes were equipped.Volkmann, Kelsey
"Boeing gets OK for new carbon brakes."
''St. Louis Business Journal'' via ''bizjournals.com.'' Retrieved: April 22, 2010.
On a 737-800 this gives a 0.5% improvement in fuel efficiency. 737s are not equipped with fuel dump systems. The original design was too small to require this, and adding a fuel dump system to the later, larger variants would have incurred a large weight penalty. Boeing instead demonstrated an "equivalent level of safety". Depending on the nature of the emergency, 737s either circle to burn off fuel or land overweight. If the latter is the case, the aircraft is inspected by maintenance personnel for damage and then returned to service if none is found. File:Boeing 737-200 planform view.jpg, The original 737 with
JT8D The Pratt & Whitney JT8D is a low-bypass (0.96 to 1) turbofan engine introduced by Pratt & Whitney in February 1963 with the inaugural flight of the Boeing 727. It was a modification of the Pratt & Whitney J52 turbojet engine which powered the ...
engines that span the entire wing chord File:Transaero b737-400 planform ei-cxk arp.jpg, The
737 Classic The Boeing 737 Classic is a series of narrow-body airliners produced by Boeing Commercial Airplanes, the second generation of the Boeing 737 series of aircraft. Development began in 1979 and the first variant, the 737-300, first flew in Febru ...
with larger
CFM56 The CFM International CFM56 (U.S. military designation F108) series is a Franco-American family of high-bypass turbofan aircraft engines made by CFM International (CFMI), with a thrust range of . CFMI is a 50–50 joint-owned company of Safran ...
s File:Boeing 737-79P, China Eastern Airlines JP6128143.jpg, The 737NG with improved CFM56-7 engines  File:PK-LQJ.jpg, The
737 MAX The Boeing 737 MAX is the fourth generation of the Boeing 737, a narrow-body airliner manufactured by Boeing Commercial Airplanes (BCA), a division of American company Boeing. It succeeds the Boeing 737 Next Generation (NG) and competes with th ...
has larger
CFM LEAP The CFM International LEAP ("Leading Edge Aviation Propulsion") is a high-bypass turbofan engine produced by CFM International, a 50–50 joint venture between American GE Aviation and French Safran Aircraft Engines (formerly Snecma). It is th ...
engines with chevrons


Engines

Engines on the 737 Classic series (-300, -400, -500) and Next-Generation series (-600, -700, -800, -900) do not have circular inlets like most aircraft but rather a planform on the lower side, which has been dictated largely by the need to accommodate ever larger engine diameters. The 737 Classic series featured
CFM56 The CFM International CFM56 (U.S. military designation F108) series is a Franco-American family of high-bypass turbofan aircraft engines made by CFM International (CFMI), with a thrust range of . CFMI is a 50–50 joint-owned company of Safran ...
high bypass
turbofan The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft engine, aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which ac ...
engines, which were 25% more efficient and also reduced noise significantly over
JT8D The Pratt & Whitney JT8D is a low-bypass (0.96 to 1) turbofan engine introduced by Pratt & Whitney in February 1963 with the inaugural flight of the Boeing 727. It was a modification of the Pratt & Whitney J52 turbojet engine which powered the ...
low bypass engines used on the 737 Original series (-100 and -200), but also posed an engineering challenge given the low ground clearance of the Boeing 737 family. Boeing and engine supplier
CFM International CFM International is a 50/50 Franco-American joint venture between GE Aviation and Safran Aircraft Engines (formerly known as Snecma). It was formed to build and support the CFM56 series of turbofan engines. The company is the world’s lead ...
(CFMI) solved the problem by placing the engine ahead of (rather than below) the wing, and by moving engine accessories to the sides (rather than the bottom) of the engine pod, giving the 737 Classic and later generations a distinctive non-circular air intake. The improved, higher pressure ratio CFM56-7 turbofan engine on the 737 Next Generation is 7% more fuel-efficient than the previous CFM56-3 on the 737 Classic with the same bypass ratio. The newest 737 variants, the 737 MAX series, feature LEAP-1B engines from CFMI with a fan diameter. These engines were expected to be 10-12% more efficient than the CFM56-7B engines on the 737 Next Generation series.


Flight systems

The 737 is unusual in that it still uses a hydro-mechanical flight control system, similar to the Boeing 707 and typical of the period, that transmits pilot commands to control surfaces via steel cables that run through the fuselage and wings, rather than by an electrical
fly-by-wire Fly-by-wire (FBW) is a system that replaces the conventional manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic signals transmitted by wires, and flight control ...
system as used across the entire Airbus fleet and all subsequent Boeing models. This has been raised as a safety issue because of the impracticality of adding redundant mechanical cable-based systems like the ones found in electronic systems. This leaves the flight controls as a single point of failure, vulnerable to wing or fuselage penetration by metal fragments from an
uncontained engine failure A turbine engine failure occurs when a turbine engine unexpectedly stops producing power due to a malfunction other than fuel exhaustion. It often applies for aircraft, but other turbine engines can fail, like ground-based turbines used in powe ...
, for example. The primary flight controls have mechanical backups. In the event of total hydraulic system failure or double engine failure, they will automatically and seamlessly revert to control via
servo tab __NOTOC__ A servo tab is a small hinged device installed on an aircraft control surface to assist the movement of the control surfaces. Introduced by the German firm Flettner, servo tabs were formerly known as Flettner tabs. Servo tabs are not ...
. In this mode, the servo tabs aerodynamically control the elevators and ailerons; these servo tabs are in turn controlled by cables running to the control yoke. The pilot's muscle forces alone control the tabs. The 737 Next Generation series introduced a six-screen LCD
glass cockpit A glass cockpit is an aircraft cockpit that features electronic (digital) flight instrument displays, typically large LCD screens, rather than the traditional style of analog dials and gauges. While a traditional cockpit relies on numerous ...
with modern avionics but designed to retain crew commonality with previous 737 generations. The 737 MAX introduced a 4 15.1 inch landscape LCD screen cockpit manufactured by
Rockwell Collins Rockwell Collins was a multinational corporation headquartered in Cedar Rapids, Iowa, providing avionics and information technology systems and services to government agencies and aircraft manufacturers. It was formed when the Collins Radio Comp ...
derived from the
Boeing 787 Dreamliner The Boeing 787 Dreamliner is an American wide-body jet airliner developed and manufactured by Boeing Commercial Airplanes. After dropping its unconventional Sonic Cruiser project, Boeing announced the conventional 7E7 on January 29, 2003, ...
. Except for the spoilers, which are fly-by-wire controlled, and all the analog instruments, which became digital, everything else is similar to the cockpits of the previous 737 generations to maintain commonality.


Aerodynamics

The Original -100 and -200 series were built without
wingtip devices Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft' ...
, but these were later introduced to improve fuel efficiency. The 737 has evolved four winglet types: the 737-200 Mini-winglet, 737 Classic/NG Blended Winglet, 737 Split Scimitar Winglet, and 737 MAX Advanced Technology Winglet. The 737-200 Mini-winglets are part of the Quiet Wing Corp modification kit that received certification in 2005. Blended winglets were standard on the 737 NG and are available for retrofit on 737 Classic models. These winglets stand approximately tall and are installed at the wing tips. They improve fuel efficiency by up to 5% through lift-induced drag reduction achieved by moderating
wingtip vortices Wingtip vortices are circular patterns of rotating air left behind a wing as it generates lift.Clancy, L.J., ''Aerodynamics'', section 5.14 One wingtip vortex trails from the tip of each wing. Wingtip vortices are sometimes named ''trailing ...
. Split Scimitar winglets became available in 2014 for the 737-800, 737-900ER, BBJ2 and BBJ3, and in 2015 for the 737-700, 737-900 and BBJ1. Split Scimitar winglets were developed by
Aviation Partners Aviation Partners Inc. (API) is a Seattle-based private corporation that specializes in performance-enhancing winglet systems. The corporation was founded in 1991 and is owned by The Washington Companies. History API was founded in 1991 by Joe Cl ...
, the same Seattle-based corporation that developed the blended winglets; the Split Scimitar winglets produce up to a 5.5% fuel savings per aircraft compared to 3.3% savings for the blended winglets. Southwest Airlines flew their first flight of a 737-800 with Split Scimitar winglets on April 14, 2014. The next generation 737, 737 MAX, will feature an Advanced Technology (AT) Winglet that is produced by Boeing. The Boeing AT Winglet resembles a cross between the Blended Winglet and the Split Scimitar Winglet. An optional Enhanced Short Runway Package was developed for use on short runways.


Interior

The first generation Original series 737 cabin was replaced for the second generation Classic series with a design based on the
Boeing 757 The Boeing 757 is an American narrow-body airliner designed and built by Boeing Commercial Airplanes. The then-named 7N7, a twinjet successor for the 727 (a trijet), received its first orders in August 1978. The prototype completed its mai ...
cabin. The Classic cabin was then redesigned once more for the third, Next Generation, 737 with a design based on the
Boeing 777 The Boeing 777, commonly referred to as the Triple Seven, is an American long-range wide-body airliner developed and manufactured by Boeing Commercial Airplanes. It is the world's largest twinjet. The 777 was designed to bridge the gap betw ...
cabin. Boeing later offered the redesigned Sky Interior on the NG. The principle features of the Sky Interior include: sculpted sidewalls, redesigned window housings, increased headroom and LED
mood lighting Mood lighting is igniting or illumination, designed to create a temporary state of mind or feeling. Effects of lighting on humans Field studies have shown in office settings that blue-enriched lighting over the course of several weeks can lead ...
,Kingsley-Jones, Max
"Narrow margins: Airbus and Boeing face pressue with the A-320 and 737."
''flightglobal.com'', October 27, 2009. Retrieved: June 23, 2010.
"Check Out Boeing's Swanky New High-Tech Interior."
''businessinsider.com.'' Retrieved: November 1, 2011.
larger pivot-bins based on the 777 and 787 designs and generally more luggage space, and claims to have improved cabin noise levels by 2–4 dB. The first 737 equipped Boeing Sky Interior was delivered to
Flydubai Flydubai ( ar, فلاي دبي), legally Dubai Aviation Corporation ( ar, مؤسسة دبي للطيران), is an Emirati government-owned low-cost airline in Dubai, United Arab Emirates with its head office and flight operations in Terminal 2 ...
in late 2010. Continental Airlines,
Alaska Airlines Alaska Airlines is a major American airline headquartered in SeaTac, Washington, within the Seattle metropolitan area. It is the sixth largest airline in North America when measured by fleet size, scheduled passengers carried, and the num ...
,
Malaysia Airlines Malaysia Airlines Berhad (MAB; ms, Penerbangan Malaysia Berhad), formerly known as Malaysian Airline System (MAS; ), and branded as Malaysia Airlines, is the flag carrier airline of Malaysia and a member of the Oneworld airline alliance. (Th ...
, and
TUIFly TUI fly Deutschland, formerly ''TUIfly'', is a German leisure airline owned by the travel and tourism company TUI Group. It is headquartered at Hannover Airport with bases at several other German airports. TUI fly Deutschland is part of TUI Gr ...
have also received Sky Interior-equipped 737s.


Other variants


737 AEW&C

The
Boeing 737 AEW&C The Boeing 737 AEW&C is a twin-engine airborne early warning and control aircraft based on the Boeing 737 Next Generation design. It is lighter than the 707-based Boeing E-3 Sentry, and has a fixed, active electronically scanned array radar ant ...
is a 737-700IGW roughly similar to the 737-700ER. This is an Airborne Early Warning and Control (AEW&C) version of the 737NG. Australia is the first customer (as Project Wedgetail), followed by
Turkey Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a transcontinental country located mainly on the Anatolian Peninsula in Western Asia, with a small portion on the Balkan Peninsula in ...
and South Korea.


T-43/CT43A

The T-43 was a 737-200 modified for use by the
United States Air Force The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...
for training navigators, now known as USAF combat systems officers. Informally referred to as the ''Gator'' (an abbreviation of "navigator") and "Flying Classroom", nineteen of these aircraft were delivered to the Air Training Command at
Mather AFB Mather Air Force Base (Mather AFB) was a United States Air Force Base, which was closed in 1993 pursuant to a post-Cold War BRAC decision. It was located east of Sacramento, on the south side of U.S. Route 50 in Sacramento County, Californ ...
, California during 1973 and 1974. Two additional aircraft were delivered to the Colorado Air National Guard at Buckley ANGB (later
Buckley AFB Buckley Space Force Base is a United States Space Force base in Aurora, Colorado named after United States Army Air Service First lieutenant, First Lieutenant John Harold Buckley. The base is run by Space Base Delta 2, with major units including ...
) and
Peterson AFB Peterson Space Force Base, previously Peterson Air Force Base, Peterson Field, and Army Air Base, Colorado Springs, is a U.S. Space Force Base that shares an airfield with the adjacent Colorado Springs Municipal Airport and is home to the No ...
, Colorado, in direct support of cadet air navigation training at the nearby U.S. Air Force Academy. Two T-43s were later converted to CT-43As, similar to the CT-40A Clipper below, in the early 1990s and transferred to Air Mobility Command and
United States Air Forces in Europe United may refer to: Places * United, Pennsylvania, an unincorporated community * United, West Virginia, an unincorporated community Arts and entertainment Films * ''United'' (2003 film), a Norwegian film * ''United'' (2011 film), a BBC Two f ...
, respectively, as executive transports. A third aircraft was also transferred to Air Force Materiel Command for use as a radar test bed aircraft and was redesignated as an NT-43A. The T-43 was retired by the
Air Education and Training Command Air Education and Training Command (AETC) is one of the nine List of major commands of the United States Air Force, Major Commands (MAJCOM) of the United States Air Force (USAF), reporting to Headquarters, United States Air Force. It was establis ...
in 2010 after 37 years of service.


C-40 Clipper

The
Boeing C-40 Clipper The Boeing C-40 Clipper is a military version of the Boeing 737 Next Generation used to transport cargo and passengers. It is used by the United States Navy, Air Force, and Marine Corps. The Navy C-40A variant is named "Clipper", whereas the ...
is a military version of the 737-700C NG. It is used by both the
United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
and the
United States Air Force The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...
, and has been ordered by the
United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through combi ...
. Technically, only the Navy C-40A variant is named "Clipper", whereas the USAF C-40B/C variants are officially unnamed.


P-8 Poseidon

The
P-8 Poseidon The Boeing P-8 Poseidon is an American maritime patrol and reconnaissance aircraft developed and produced by Boeing Defense, Space & Security, and derived from the civilian Boeing 737-800. It was developed for the United States Navy (USN). Th ...
developed for the
United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
by
Boeing Defense, Space & Security Boeing Defense, Space & Security (BDS) is a division (business unit) of The Boeing Company based in Arlington, Virginia. It is responsible for defense and aerospace products and services. It was formerly known as Boeing Integrated Defense System ...
, based on the Next Generation 737-800ERX. The P-8 can be operated in the
anti-submarine warfare Anti-submarine warfare (ASW, or in older form A/S) is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are t ...
(ASW),
anti-surface warfare Anti-surface warfare (ASuW or ASUW) is the branch of naval warfare concerned with the suppression of surface combatants. More generally, it is any weapons, sensors, or operations intended to attack or limit the effectiveness of an adversary's s ...
(ASUW), and shipping interdiction roles. It is armed with
torpedo A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target. Historically, s ...
es, Harpoon anti-ship missiles and other weapons, and is able to drop and monitor
sonobuoy A sonobuoy (a portmanteau of sonar and buoy) is a relatively small buoy – typically diameter and long – expendable sonar system that is dropped/ejected from aircraft or ships conducting anti-submarine warfare or underwater acoustic rese ...
s, as well as operate in conjunction with other assets such as the
Northrop Grumman MQ-4C Triton The Northrop Grumman MQ-4C Triton is an American high-altitude long endurance unmanned aerial vehicle (UAV) under development for the United States Navy as a surveillance aircraft. Together with its associated ground control station, it is an ...
maritime surveillance
unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controll ...
(UAV).


Boeing Business Jet (BBJ)

In the late 1980s, Boeing marketed the 77-33 jet, a business jet version of the 737-300. The name was short-lived. After the introduction of the Next Generation series, Boeing introduced the Boeing Business Jet (BBJ) series. The BBJ1 was similar in dimensions to the 737-700 but had additional features, including stronger wings and landing gear from the 737-800, and had increased range over the other 737 models through the use of extra fuel tanks. The first BBJ rolled out on August 11, 1998, and flew for the first time on September 4."The Boeing 737-700/800 BBJ/BBJ2."
''airliners.net''. Retrieved: February 3, 2008.
On October 11, 1999, Boeing launched the BBJ2. Based on the 737-800, it is longer than the BBJ, with 25% more cabin space and twice the baggage space, but has slightly reduced range. It is also fitted with auxiliary belly fuel tanks and winglets. The first BBJ2 was delivered on February 28, 2001. Boeing's BBJ3 is based on the 737-900ER. The BBJ3 has of floor space, 35% more interior space, and 89% more luggage space than the BBJ2. It has an auxiliary fuel system, giving it a range of up to , and a
Head-up display A head-up display, or heads-up display, also known as a HUD (), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a pilot being able to view informa ...
. Boeing completed the first example in August 2008. This aircraft's cabin is pressurized to a simulated altitude.


Boeing Converted Freighter program

The Boeing Converted Freighter program (BCF), or the 737-800BCF program, was launched by Boeing in 2016. It converts old 737-800 passenger jets to dedicated freighters. The first 737-800BCF was delivered in 2018 to GECAS, which is leased to
West Atlantic West Atlantic is a holding company for two European cargo airlines, West Air Sweden and West Atlantic UK, with its head office in Malmö, Sweden. West Atlantic employ some 650 staff and operate a fleet of 22 aircraft. The airline specializes in ...
. Boeing has signed an agreement with Chinese YTO Cargo Airlines to provide the airline with 737-800BCFs pending a planned program launch.


Experimental

Three 737 aircraft have been used in Boeing test programs. In 2012, a new 737-800 bound for American Airlines became the first ecoDemonstrator airframe in a program that continues annually into the 2020s. In conjunction with many industry partners, the program aims to reduce the
environmental impact of aviation Like other emissions resulting from fossil fuel combustion, aircraft engines produce gases, noise, and particulates, raising environmental concerns over their global effects and their effects on local air quality. Jet airliners contribute to ...
. In 2012 it tested the winglets which would eventually be used in the 737 MAX series. Testing also included a variable area exhaust nozzle, regenerative hydrogen fuel cells for electrical power, and
sustainable aviation fuel An aviation biofuel or bio-jet fuel Note: About">Investable Universe>About' or bio-aviation fuel (BAF) is a biofuel used to power aircraft and is said to be a sustainable aviation fuel (SAF). The International Air Transport Association (IATA) co ...
(SAF). In 2018, one of the 737 MAX 7 prototypes participated in Boeing's
Quiet Technology Demonstrator The ecoDemonstrator Program is a Boeing flight test research program, which has used a series of specially modified aircraft to develop and test aviation technologies designed to improve fuel economy and reduce the noise and ecological footprin ...
3 (QTD3) program, in which a
NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
engine inlet designed to reduce engine noise was tested over an acoustic array at
Moses Lake Moses Lake is a lake and reservoir along the course of Crab Creek, in Washington state, USA. Moses Lake is part of the Columbia River basin, as Crab Creek is a tributary of the Columbia River. Although originally a shallow natural lake, Moses ...
,
Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...
. A 737 MAX 9 was used as the 2021 ecoDemonstrator. A new airframe in a special Alaska Airlines livery flew an extensive test program, a major part of which was the use of SAF in blends of up to 50% including a flight from Seattle to
Glasgow Glasgow ( ; sco, Glesca or ; gd, Glaschu ) is the most populous city in Scotland and the fourth-most populous city in the United Kingdom, as well as being the 27th largest city by population in Europe. In 2020, it had an estimated popul ...
,
Scotland Scotland (, ) is a Countries of the United Kingdom, country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a Anglo-Scottish border, border with England to the southeast ...
, to attend the United Nations COP26 Climate Change Conference. Other test areas included halon-free fire extinguisher (ground testing only), a low-profile
anti-collision light Anti-collision lights, also known as Beacon lights or Strobe lights are a set of lights required on every aircraft to improve visibility to others, as well as collision avoidance measures by warning other pilots. Historically they have used incandes ...
, and text-based
air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airs ...
communications. At the end of the testing the aircraft was returned to standard configuration, and was delivered to Alaska Airlines in 2022.


Competition

The Boeing 737 Classic, Next Generation and MAX series have faced significant competition from the
Airbus A320 family The Airbus A320 family is a series of Narrow-body aircraft, narrow-body airliners developed and produced by Airbus. The A320 was launched in March 1984, Maiden flight, first flew on 22 February 1987, and was introduced in April 1988 by Air F ...
first introduced in 1988. The relatively recent
Airbus A220 family The Airbus A220 is a family of five-abreast narrow-body airliners by Airbus Canada Limited Partnership. It was originally designed by Bombardier Aerospace, Bombardier and had two years in service as the Bombardier CSeries. The program was ...
now also competes against the smaller capacity end of the 737 variants. The A320 was developed to compete also with the McDonnell Douglas MD-80/90 and 95 series; the 95 later becoming the
Boeing 717 The Boeing 717 is an American five-abreast single-aisle airliner produced by Boeing Commercial Airplanes. The twin-engine airliner was developed for the 100-seat market and originally marketed by McDonnell Douglas as the MD-95. It was a shor ...
. Since July 2017, Airbus had a 59.4% market share of the re-engined single aisle market, while Boeing had 40.6%; Boeing had doubts on over-ordered A320neos by new operators and expected to narrow the gap with replacements not already ordered. However, in July 2017, Airbus had still 1,350 more A320neo orders than Boeing had for the 737 MAX. Boeing delivered 8,918 of the 737 family between March 1988 and December 2018, while
Airbus Airbus SE (; ; ; ) is a European multinational aerospace corporation. Airbus designs, manufactures and sells civil and military aerospace products worldwide and manufactures aircraft throughout the world. The company has three divisions: ' ...
delivered 8,605 A320 family aircraft over a similar period since first delivery in early 1988. * *


Operators

, the five largest operators of the Boeing 737 were Southwest Airlines (736), Ryanair (443),
United Airlines United Airlines, Inc. (commonly referred to as United), is a major American airline headquartered at the Willis Tower in Chicago, Illinois.
(383),
American Airlines American Airlines is a major airlines of the United States, major US-based airline headquartered in Fort Worth, Texas, within the Dallas–Fort Worth metroplex. It is the Largest airlines in the world, largest airline in the world when measured ...
(344), and
Delta Air Lines Delta Air Lines, Inc., typically referred to as Delta, is one of the major airlines of the United States and a legacy carrier. One of the world's oldest airlines in operation, Delta is headquartered in Atlanta, Georgia. The airline, along w ...
(218).


Civilian

In 2006, over 4,500 Boeing 737s were operated by more than 500 airlines, flying to 1,200 destinations in 190 countries and on average 1,250 aircraft were airborne, with two either departing or landing every five seconds. The 737 was the most commonly flown aircraft in 2008, 2009, and 2010. In 2013, over 5,580 Boeing 737s were operated by more than 342 airlines in 111 countries, which represented more than 25% of the worldwide fleet of large jet airliners. The 737 had carried over 16.8 billion passengers (twice of 7.1 billion world population in that time) over 119 billion miles (192 billion km) with more than 184 million flights or 264 million hours in the air. In 2016, there were 6,512 Boeing 737 airliners in service (5,567 737NGs plus 945 737-200s and
737 Classic The Boeing 737 Classic is a series of narrow-body airliners produced by Boeing Commercial Airplanes, the second generation of the Boeing 737 series of aircraft. Development began in 1979 and the first variant, the 737-300, first flew in Febru ...
s), more than the 6,510 Airbus A320 family. while in 2017, there were 6,858 737s in service (5,968 737NGs plus 890 737-200s and classics), fewer than the 6,965 A320 family. , despite being the world most delivered airliner, 9,315 Boeing 737s were in service, slightly fewer than the 9,353 A320 family, as more 737s were already out of service.


Military

Many countries operate the 737 passenger, BBJ, and cargo variants in government or military applications. Users with 737s include: * * * * * * * * * * * * * * * * * * * * * * * * * * *


Orders and deliveries

The 737 had the highest, cumulative orders for any airliner until surpassed by the A320 family in October 2019. In that year, 737 orders dropped by 90%, as 737 MAX orders dried up after the March grounding. The 737 MAX backlog fell by 182, mainly due to the
Jet Airways Jet Airways (India) Ltd is an Indian airline based in Delhi NCR, with a training and developmental center in Mumbai. Incorporated in April 1992 as a limited liability company, the airline began operations as an air taxi operator in 1993. It b ...
bankruptcy, a drop in Boeing's airliner backlog was a first in at least the past 30 years. , 15,472 units of the Boeing 737 family had been ordered, with 4,262 orders were pending, or 3,578 when including "additional criteria for recognizing contracted backlog with customers beyond the existence of a firm contract" (ASC 606 Adjustment). Boeing delivered the 5,000th 737 to Southwest Airlines on February 13, 2006, the 6,000th 737 to
Norwegian Air Shuttle Norwegian Air Shuttle ASA, trading as Norwegian, is a Norwegian low-cost airline and Norway's largest airline. It is the fourth largest low-cost carrier in Europe behind Wizz Air, easyJet and Ryanair, the second-largest airline in Scandinavia ...
in April 2009, the 7,000th 737 to
Flydubai Flydubai ( ar, فلاي دبي), legally Dubai Aviation Corporation ( ar, مؤسسة دبي للطيران), is an Emirati government-owned low-cost airline in Dubai, United Arab Emirates with its head office and flight operations in Terminal 2 ...
on December 16, 2011, the 8,000th 737 to
United Airlines United Airlines, Inc. (commonly referred to as United), is a major American airline headquartered at the Willis Tower in Chicago, Illinois.
on April 16, 2014, and the 9,000th 737 to
China United Airlines China United Airlines Co., Ltd. () is a low-cost carrier and a subsidiary of China Eastern Airlines with its headquarters and main hub on the grounds of Beijing Daxing International Airport in Daxing District, Beijing, operating scheduled fl ...
in April 2016. The 10,000th 737 was ordered in July 2012, rolled out on March 13, 2018, and was to be delivered to Southwest Airlines; the backlog at the time stood at over 4,600 aircraft. , 11,210 units of the Boeing 737 family had been delivered, while 10,616 of the competing A320 family had been delivered.


Model summary


Accidents and incidents

, there has been a total of 503
aviation accidents and incidents An aviation accident is defined by the Convention on International Civil Aviation Annex 13 as an occurrence associated with the operation of an aircraft, which takes place from the time any person boards the aircraft with the ''intention of fl ...
involving all 737 aircraft, including 219
hull loss A hull loss is an aviation accident that catastrophically damages the aircraft beyond economical repair, resulting in a total loss. The term also applies to situations in which the aircraft is missing, the search for their wreckage is terminate ...
es resulting in a total of 5,717 fatalities. A Boeing analysis of commercial jet airplane accidents between 1959 and 2013 found that the hull loss rate for the Original series was 1.75 per million departures, for the Classic series 0.54, and the Next Generation series 0.27. During the 1990s, a series of rudder issues on series -200 and -300 aircraft resulted in multiple incidents. In two total loss accidents,
United Airlines Flight 585 United Airlines Flight 585 was a scheduled passenger flight on March 3, 1991 from Denver to Colorado Springs, Colorado, carrying 20 passengers and 5 crew members on board. The plane experienced a rudder hardover while on final approach to runway ...
(a -200 series) and
USAir Flight 427 USAir Flight 427 was a scheduled flight from Chicago's O'Hare International Airport to Palm Beach International Airport, Florida, with a stopover at Pittsburgh International Airport. On Thursday, September 8, 1994, the Boeing 737 flying this r ...
, (a -300), the pilots lost control of the aircraft following a sudden and unexpected deflection of the
rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally air or water). On an aircraft the rudder is used primarily to counter adve ...
, killing everyone aboard, a total of 157 people. Similar rudder issues led to a temporary loss of control on at least five other 737 flights before the problem was ultimately identified. The National Transportation Safety Board determined that the accidents and incidents were the result of a design flaw that could result in an uncommanded movement of the aircraft's rudder. As a result of the NTSB's findings, the
Federal Aviation Administration The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic ...
ordered that the rudder servo valves be replaced on all 737s and mandated new training protocols for pilots to handle an unexpected movement of control surfaces. Following the crashes of two 737 MAX 8 aircraft,
Lion Air Flight 610 Lion Air Flight 610 was a scheduled domestic passenger flight from Soekarno–Hatta International Airport, Jakarta to Depati Amir Airport, Pangkal Pinang in Indonesia. On 29 October 2018, the Boeing 737 MAX operating the route crashed into th ...
in October 2018 and
Ethiopian Airlines Flight 302 Ethiopian Airlines Flight 302 was a scheduled international passenger flight from Addis Ababa Bole International Airport in Ethiopia to Jomo Kenyatta International Airport in Nairobi, Kenya. On 10 March 2019, the Boeing 737 MAX 8 aircraft ...
in March 2019, which caused 346 deaths, civil aviation authorities around the world grounded the 737 MAX series. On December 16, 2019, Boeing announced that it would suspend production of the 737 MAX from January 2020. Production of the MAX series resumed on May 27, 2020.


Aircraft on display

Owing to the 737's long production history and popularity, many older 737s have found use in museums after reaching the end of useful service. * 19437/1: 737-130 registered N515NA on static display at the
Museum of Flight The Museum of Flight is a private non-profit air and space museum in the Seattle metropolitan area. It is located at the southern end of King County International Airport (Boeing Field) in the city of Tukwila, immediately south of Seattle. ...
in
Seattle, Washington Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest region ...
. It was the first 737 built and is painted in NASA markings. * 19047/14: 737-222 registered N9009U preserved by
Southern Illinois University Carbondale Southern Illinois University (SIU or SIUC) is a public research university in Carbondale, Illinois. Founded in 1869, SIU is the oldest and flagship campus of the Southern Illinois University system. The university enrolls students from all 50 st ...
at Southern Illinois Airport. * 20213/160: 737-201 registered N213US forward fuselage on static display at the
Museum of Flight The Museum of Flight is a private non-profit air and space museum in the Seattle metropolitan area. It is located at the southern end of King County International Airport (Boeing Field) in the city of Tukwila, immediately south of Seattle. ...
in Seattle, Washington, in
USAir US Airways (formerly USAir) was a major United States airline that operated from 1937 until its merger with American Airlines in 2015. It was originally founded in Pittsburgh as a mail delivery airline called All American Aviation, which soon b ...
livery. * 20561/292: 737-281 registered LV-WTX on static display at the National Museum of Aeronautics in
Morón, Buenos Aires Morón () is a city in the Argentine province of Buenos Aires, capital of the Morón ''partido'', located in the Greater Buenos Aires metropolitan area, at . Located 20 km (13 mi) west of Downtown Buenos Aires, Morón is easily reac ...
. * 20562/293: 737-281 registered CC-CSK fuselage preserved at Motel Bahía in
Concón Concón is a Chilean city and commune in Valparaíso Province, Valparaíso Region. It is a major tourist center known for its beaches, ''balnearios'' (beachside resorts) and night life. Geography The commune of Concón spans an area of . It is ...
,
Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
. * 21262/470: 737-2H4 registered C-GWJT on static display at the
British Columbia Institute of Technology The British Columbia Institute of Technology (also referred to as BCIT), is a public polytechnic institute in Burnaby, British Columbia. The technical institute has five campuses located in the Metro Vancouver region, with its main campus in B ...
Aerospace Technology Campus in
Richmond, British Columbia Richmond is a coastal city in the Lower Mainland region of British Columbia, Canada. It occupies almost the entirety of Lulu Island (excluding Queensborough), between the two estuarine distributaries of the Fraser River. Encompassing the adja ...
. It is used for ground instructional training. The aircraft was donated by
WestJet WestJet Airlines Ltd. is a Canadian airline headquartered in Calgary, Alberta, near Calgary International Airport. It is the second-largest Canadian airline, behind Air Canada, operating an average of 777 flights and carrying more than 66,130 ...
and bears its livery. * 21340/499: 737-2H4 registered N29SW on static display at the Kansas Aviation Museum in
Wichita, Kansas Wichita ( ) is the largest city in the U.S. state of Kansas and the county seat of Sedgwick County. As of the 2020 census, the population of the city was 397,532. The Wichita metro area had a population of 647,610 in 2020. It is located in ...
. It was formerly operated by Ryan International Airlines and prior to that Southwest Airlines. * 21712/557: 737-275 registered C-GIPW preserved in operational condition at
Alberta Flying Heritage Museum The Alberta Flying Heritage Museum was a proposed aviation museum for the Edmonton/Villeneuve Airport in Villeneuve, Alberta, Canada in order to move the Alberta Aviation Museum collection out of the City of Edmonton as a result of the closure ...
in Villeneuve,
Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...
. Painted in
Pacific Western Airlines Pacific Western Airlines Ltd (PWA) was an airline that operated scheduled flights throughout western Canada and charter services around the world from the 1950s through the 1980s. It was headquartered at Vancouver International Airport in Ri ...
livery. * 22578/767: 737-290C registered N740AS on static display at the Alaska Aviation Heritage Museum in Anchorage, Alaska. It was formerly operated by
Alaska Airlines Alaska Airlines is a major American airline headquartered in SeaTac, Washington, within the Seattle metropolitan area. It is the sixth largest airline in North America when measured by fleet size, scheduled passengers carried, and the num ...
. * 22826/878: 737-2H4 registered YV1361 preserved at a hotel in
Santiago Santiago (, ; ), also known as Santiago de Chile, is the capital and largest city of Chile as well as one of the largest cities in the Americas. It is the center of Chile's most densely populated region, the Santiago Metropolitan Region, whos ...
,
Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
. It was formerly operated by Avior Airlines. * 23059/980: 737-2Z6 registered 22–222 on static display at the
Royal Thai Air Force Museum The Royal Thai Air Force Museum is located in Don Mueang District, Bangkok, Thailand. It is located on the Phahonyothin Road just to the south of Wing 6 of the domestic terminal of the Don Mueang Airport. It was served by the Royal Thai Air Force ...
in
Bangkok Bangkok, officially known in Thai as Krung Thep Maha Nakhon and colloquially as Krung Thep, is the capital and most populous city of Thailand. The city occupies in the Chao Phraya River delta in central Thailand and has an estimated populati ...
. * 22940/1037: 737-3H4 registered N300SW on static display at the Frontiers of Flight Museum in
Dallas, Texas Dallas () is the third largest city in Texas and the largest city in the Dallas–Fort Worth metroplex, the fourth-largest metropolitan area in the United States at 7.5 million people. It is the largest city in and seat of Dallas County ...
. It was the first such aircraft delivered to Southwest Airlines in November 1984. * 23257/1124: 737-301 registered PK-AWU on static display at
ITE College Central ITE College Central (ITECC) is a post-secondary education institution and statutory board under the purview of the Ministry of Education in Singapore. It is one of the Institute of Technical Education's three colleges under the "One ITE System, ...
in
Singapore Singapore (), officially the Republic of Singapore, is a sovereign island country and city-state in maritime Southeast Asia. It lies about one degree of latitude () north of the equator, off the southern tip of the Malay Peninsula, bor ...
. * 23472/1194: 737-219 registered ZS-SMD on static display at the South African Airways Museum in
Germiston, Gauteng Germiston, also known as kwaDukathole, is a small city in the East Rand region of Gauteng, South Africa, administratively forming part of the City of Ekurhuleni Metropolitan Municipality since the latter's establishment in 2000. It functions as ...
. * 23660/1294: 737-377 registered G-CELS (nickname Elsie) on static display at Norwich International Aviation Academy, as an aircraft maintenance trainer. It is painted in the silver & red
Jet2.com Jet2.com Limited is a British low-cost leisure airline offering scheduled and charter flights from the United Kingdom. As of 2022, it is the third-largest scheduled airline in the UK, behind EasyJet and British Airways. Jet2 is also officia ...
colour scheme, without the logo branding. * 27286/2528: 737-3Q8 registered N759BA on static display at the
Pima Air & Space Museum The Pima Air & Space Museum, located in Tucson, Arizona, is one of the world's largest non-government funded aerospace museums. The museum features a display of nearly 300 aircraft spread out over 80 acres (320,000 m²) on a campus oc ...
in
Tucson, Arizona , "(at the) base of the black ill , nicknames = "The Old Pueblo", "Optics Valley", "America's biggest small town" , image_map = , mapsize = 260px , map_caption = Interactive map ...
. It is painted in
China Southern Airlines China Southern Airlines Company Limited is an airline headquartered in Baiyun District, Guangzhou, Guangdong Province and is the largest airline in China. Established on 1 July 1988 following the restructuring of the CAAC Airlines that acqu ...
markings, and was previously operated by the airline as B-2921.


Specifications


See also


References


Citations


Bibliography

* * * * * * * * * * *


External links


737 page on Boeing.com

The 737 Story on FlightInternational.com
* {{Authority control Aircraft first flown in 1967
737 737 most commonly refers to: * Boeing 737, an American narrow-body passenger airplane ** Boeing 737 Classic ** Boeing 737 MAX ** Boeing 737 Next Generation * AD 737, a year in the common era * 737 BC, a year * 737 (number), a number 737 may als ...
Low-wing aircraft Twinjets 1960s United States airliners