A national aviation authority (NAA) or civil aviation authority is a government statutory authority in each country that maintains an aircraft register and oversees the approval and regulation of civil aviation.
Depending on the legal system of the jurisdiction, a NAA will derive its powers from an act of parliament (such as the Civil or Federal Aviation Act), and is then empowered to make regulations within the bounds of the act. This allows technical aspects of airworthiness to be dealt with by subject matter experts and not politicians.
A NAA may also be involved in the investigation of aircraft accidents, although in many cases this is left to a separate body (such as the Australian Transport Safety Bureau (ATSB) in Australia or the National Transportation Safety Board (NTSB) in the United States), to allow independent review of regulatory oversight.
A NAA will regulate the control of air traffic but a separate agency will generally carry out air traffic control functions.
In some countries an NAA may build and operate airports, including non-airside operations such as passenger terminals; the Civil Aviation Authority of Nepal and the Civil Aviation Authority of the Philippines being among such national authorities. In other countries, private companies or local government authorities may own and operate individual airports.
The independent development of NAAs resulted in differing regulations from country to country. This required aircraft manufacturers in the past to develop different models for specific national requirements (such as the BAe Jetstream 31), and impeded airline travel into foreign jurisdictions. The Convention on International Civil Aviation (Chicago Convention) was signed in 1944 and addressed these issues. This then led to the establishment by the United Nations of the International Civil Aviation Organization (ICAO) in 1947 which now oversees member states, and works to implement regulatory changes to ensure that best practice regulations are adopted.
A European Aviation Safety Agency (EASA) was created in 2003, with regulatory and executive tasks in the field of civilian aviation safety. It is not a national authority as such, and European Union members continue to have their own agencies.