The International Civil Aviation Organisation is a specialised agency responsible for codifying the principles and techniques of international air navigation and fostering the planning and development of international air transport to ensure safe and orderly growth. The ICAO headquarters are in Montreal, Canada.
ICAO was ‘born’ in Chicago in 1944 when 52 countries signed the Convention on International Civil Aviation, also known as the Chicago Convention. Since then ICAO has become a specialised agency of the United Nations and As of March 2016, there are 191 ICAO members.
The ICAO Council adopts standards and recommended practices concerning air navigation, its infrastructure, flight inspection, prevention of unlawful interference, and facilitation of border-crossing procedures for international civil aviation. ICAO also defines the protocols for air accident investigation.
It is no longer the case that the National Aviation Authorities are entirely independent. Since the Chicago Convention in 1944 the growth of aviation and its remarkable safety record has been facilitated by standardisation and international agreements.
Each ICAO member country has its own regulations which govern the use of its own airspace. The bodies empowered to create aviation regulations in each sovereign state are referred to as National Aviation Authorities (NAA).