intergovernmental specialized agency associated with the United Nations (UN). Established in 1947 by the Convention on International Civil Aviation (1944), which had been signed by 52 states three years earlier in Chicago, the ICAO is dedicated to developing safe and efficient international air transport for peaceful purposes and ensuring a reasonable opportunity for every state to operate international airlines. The organization's permanent headquarters are in Montreal.

The ICAO, whose membership includes virtually every state in the world, has several component bodies: (1) an Assembly of delegates from all member countries that meets every three years, (2) a Council of representatives from 33 member states, elected by and responsible to the Assembly, that sits in continuous session at ICAO headquarters, (3) an Air Navigation Commission appointed by the Council for addressing technical matters, and (4) various standing committees, including a Committee on Joint Support of Air Navigation Services and a Finance Committee. The ICAO's Secretariat is headed by a secretary-general selected by the Council for a three-year term. The five main sections of the Secretariat—the Air Navigation Bureau, the Air Transport Bureau, the Technical Co-operation Bureau, the Legal Bureau, and the Bureau of Administration and Services—provide technical and administrative assistance to the various national representatives.

The ICAO's activities have included establishing and reviewing international technical standards for aircraft operation and design, crash investigation, the licensing of personnel, telecommunications, meteorology, air navigation equipment, ground facilities for air transport, and search-and-rescue missions. The organization also promotes regional and international agreements aimed at liberalizing aviation markets, helps to establish legal standards to ensure that the growth of aviation does not compromise safety, and encourages the development of other aspects of international aviation law.