The first international civil aviation conference, held in 1910 and attended by European governments only, since transoceanic flight was then regarded as no more than a wild dream, was a failure. Almost another decade elapsed before an international convention, signed in Paris in 1919, created the International Commission for Air Navigation. The commission was to meet at least once a year and concern itself with technical matters. An international committee of jurists was also established, to concern itself with the intricate legal questions created by cross-border aviation. In 1928, a Pan-American convention on commercial aviation was adopted at a conference held in Havana to deal with problems then emerging as international flights became more frequent in the Western Hemisphere. Although some progress in obtaining agreement on international flight regulations had been made by the end of the 1930s, most nations still granted very few concessions to each other's airlines, and no agreement existed permitting foreign planes to fly nonstop over the territory of one country en route to another country.
The tremendous development of aviation during World War II demonstrated the need for an international organization to assist and regulate international flight for peaceful purposes, covering all aspects of flying, including technical, economic, and legal problems. For these reasons, in early 1944, the US conducted exploratory discussions with its World War II allies, on the basis of which invitations were sent to 55 allied and neutral states to meet in Chicago in November 1944.
In November and December 1944, delegates of 52 nations met at the International Civil Aviation Conference in Chicago to plan for international cooperation in the field of air navigation in the postwar era. It was this conference that framed the constitution of the International Civil Aviation Organization—the Convention on International Civil Aviation, also called the Chicago Convention. This convention stipulated that ICAO would come into being after the convention was ratified by 26 nations. To respond to the immediate needs of civil aviation, a provisional organization was created and functioned for 20 months until, on 4 April 1947, ICAO officially came into existence.
In essence, the conference was faced with two questions: (1) whether universally recognized navigational signals and other navigational and technical standards could be agreed upon, and (2) whether international rules concerning the economics of air transport could be established. One group of countries, led by the US, wanted an international organization empowered only to make recommendations regarding standard technical procedures and equipment. In its economic aspects, these countries believed, air transportation should be freely competitive. This policy would also best serve the interests of the "consumer nations" that had no international airlines of their own. Another group of countries, led by the UK, favored a stronger organization, which would have a great deal to say about the economics of civil aviation. It would be empowered to allocate the international routes that the airlines of different countries would be allowed to fly, regulate the frequency of flights, and fix rates. A radical proposal, advanced by New Zealand and supported by Australia, called for international ownership and operation of international air transport.
The Convention on International Civil Aviation finally adopted by the conference was something of a compromise between the American and British positions. The convention established for the first time an independent international body, the International Civil Aviation Organization, to supervise "order in the air," obtain maximum technical standardization for international aviation, recommend certain practices that member countries should follow, and carry out other functions. Countries ratifying or acceding to the convention thereby agreed in advance to conform to the greatest possible extent to ICAO-adopted civil aviation standards and to endeavor to conform to ICAO-adopted recommendations.
In the economic field, ICAO has no regulatory powers, but one of its constitutional objectives is to "prevent economic waste caused by unreasonable competition." In addition, under the convention, member states undertake to have their international airlines furnish ICAO with traffic reports, cost statistics, and financial statements showing, among other things, all receipts from operations and the sources of such revenues.
The Chicago Convention affirms every state's "complete and exclusive sovereignty over the airspace above its territory." It provides that nonscheduled flights may, subject to certain permissible conditions and limitations, be made by the civil aircraft of one country into or over the territory of another. Scheduled international air service, however, may be operated from one country into or over the territory of another country only with the latter's authorization, and member states are permitted to establish areas prohibited to foreign aircraft as long as these regulations are non-discriminatory. Pilotless as well as conventional aircraft are covered by these provisions. The term airspace is not precisely defined, however, and with the development of rockets and long-range missiles, the problem of deciding where a country's airspace ends and where outer space begins has become a matter of practical concern. This problem has come under study by the UN Committee on the Peaceful Uses of Outer Space.
An important matter considered by the Chicago conference was the question of the exchange of commercial rights in international civil aviation. It was not possible to reach an agreement satisfactory to all states attending the conference. Hence, the question was covered not in the Convention on International Civil Aviation that serves as ICAO's constitution but in two supplementary agreements adopted by the conference: the International Air Services Transit Agreement and the International Air Transport Agreement. These two treaties do not form part of the ICAO constitution and are binding only on the ICAO member states that have ratified them.
The International Air Services Transit Agreement guarantees (1) the freedom of civil aircraft to fly over foreign countries and territories as long as they do not land, and (2) the freedom of civil aircraft to make nontraffic landings, for refueling or overhaul only, in foreign territory. The agreement thus established for the first time the principle of automatic right of transit and of emergency landing.
The International Air Transport Agreement, also known as the Five Freedoms Agreement, affirms, in addition to the two freedoms covered by the transit agreement, three other freedoms of the air: (3) freedom to transport passengers and cargo from an aircraft's homeland to other countries, (4) freedom to transport passengers and cargo from other countries to an aircraft's homeland, and (5) freedom to carry air traffic between countries other than the aircraft's homeland.
Because the Chicago Convention was adopted in December 1944, ICAO possesses a constitution older than the UN Charter. Countries were much slower in ratifying the Chicago Convention, however, than they were in ratifying the UN Charter. For this reason, ICAO did not come into being until 4 April 1947, 30 days after the convention had been ratified by the required 26 states.