The largest airlines in the world can be defined in several ways. ,

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 List of airlines by foundation date, world's oldest airlines in operation, Delta is headquartered in Atla ...

is the largest by

revenue In accounting, revenue is the total amount of income generated by the sale of goods and services related to the primary operations of the business. Commercial revenue may also be referred to as sales or as turnover. Some companies receive reven ...

asset In financial accountancy, financial accounting, an asset is any resource owned or controlled by a business or an economic entity. It is anything (tangible or intangible) that can be used to produce positive economic value. Assets represent value ...

s value and

market capitalization Market capitalization, sometimes referred to as market cap, is the total value of a publicly traded company's outstanding common shares owned by stockholders. Market capitalization is equal to the market price per common share multiplied by t ...

, China Southern Air Holding by

passenger A passenger (also abbreviated as pax) is a person who travels in a vehicle, but does not bear any responsibility for the tasks required for that vehicle to arrive at its destination or otherwise operate the vehicle, and is not a steward. The ...

s carried and

revenue passenger mile A passenger (also abbreviated as pax) is a person who travels in a vehicle, but does not bear any responsibility for the tasks required for that vehicle to arrive at its destination or otherwise operate the vehicle, and is not a steward. The ...

American Airlines Group American Airlines Group Inc. is an American publicly traded airline holding company headquartered in Fort Worth, Texas. It was formed on December 9, 2013, by the merger of AMR Corporation, the parent company of American Airlines, and US Airways ...

by fleet size and number of

employee Employment is a relationship between two parties regulating the provision of paid labour services. Usually based on a contract, one party, the employer, which might be a corporation, a not-for-profit organization, a co-operative, or any other ...

FedEx Express FedEx Express, a subsidiary of FedEx Corporation, is a major American cargo airline based in Memphis, Tennessee, United States. As of 2020, it is one of the world's largest airlines in terms of fleet size and freight tons flown. It is the name ...

by freight

tonne-kilometer The units of measurement in transportation describes the unit of measurement used to express various transportation quantities, as used in statistics, planning, and their related applications. Transportation quantity The currently popular units ...

Ryanair Ryanair is an Irish ultra low-cost carrier founded in 1984. It is headquartered in Swords, Dublin, Ireland and has its primary operational bases at Dublin and London Stansted airports. It forms the largest part of the Ryanair Holdings family ...

by number of routes,

Turkish Airlines Turkish Airlines ( Turkish: ''Türk Hava Yolları'') is the national flag carrier airline of Turkey. , it operates scheduled services to 340 destinations in Europe, Asia, Africa, and the Americas, making it the largest mainline carrier in the w ...

by number of countries served and

UPS Airlines UPS Airlines is a major American cargo airline based in Louisville, Kentucky. The second-largest cargo airline worldwide ( in terms of freight volume flown), UPS Airlines flies to 815 destinations worldwide. A wholly owned subsidiary of UPS (Unit ...

by number of destinations served.

By company revenue

Note that

Emirates Emirates may refer to: * United Arab Emirates, a Middle Eastern country * Emirate, any territory ruled by an emir ** Gulf emirates, emirates located on the Persian Gulf ** Emirates of the United Arab Emirates, the individual emirates * The Emirat ...

is a state-owned company and is thus not included in this list of public companies. Its 2021 revenue was estimated over 18 billion USD, which would place the company into 5th place. Its 2014-2015 revenue was billion ( billion), profit billion ( billion), and assets billion ( billion), with 56,725 employees. Qatar Airways Group is similarly privately held.

By passengers carried

;Airline groups ;Airlines The

IATA The International Air Transport Association (IATA ) is a trade association of the world's airlines founded in 1945. IATA has been described as a cartel since, in addition to setting technical standards for airlines, IATA also organized tariff ...

reports numbers for individual

air operator's certificate An air operator's certificate (AOC) is the approval granted by a civil aviation authority (CAA) to an aircraft operator to allow it to use aircraft for commercial purposes. This requires the operator to have personnel, assets, and system in pla ...

s and groups of multiple airlines can report larger numbers. By passengers carried (thousands)