The Chicago Convention of 1944
Signed while the Second World War was still being fought, the Chicago Convention remains the constitution of international civil aviation.
The setting
By 1944 it was clear that the war would end with an enormous expansion in aviation capacity: trained pilots, long-range aircraft, and airfields across the world. The United States invited allied and neutral nations to Chicago to agree on how international civil aviation would work after the war. Delegates met from November into December 1944.
The central dispute was economic. The United States, with the world's largest aviation industry, favored broad freedom for airlines to compete. Many other countries feared that American carriers would dominate and preferred tight regulation of routes, capacity, and fares. The convention that emerged settled the legal foundations, but left the commercial questions largely to be negotiated country by country.
Core principles
Sovereignty over airspace
The convention affirms that every state has complete and exclusive sovereignty over the airspace above its territory. This single principle explains why international aviation requires agreements: no airline has an inherent right to enter another nation's skies.
Civil versus state aircraft
The convention applies to civil aircraft. State aircraft, including military, customs, and police aircraft, are treated separately and may not fly over or land in another state without authorization.
Scheduled and non-scheduled services
Scheduled international air services require the permission of the states concerned. This is the legal hook for the vast network of bilateral air services agreements described on the Bilateral Agreements page.
Uniform standards
States commit to cooperate on uniform regulations for aircraft, personnel, airways, and procedures. That commitment is carried out through ICAO's Standards and Recommended Practices.
The companion agreements
Two further agreements were opened for signature in Chicago:
- The International Air Services Transit Agreement, the "Two Freedoms Agreement," granting the rights to overfly and to land for non-traffic purposes such as refueling.
- The International Air Transport Agreement, the "Five Freedoms Agreement," which attempted to grant commercial traffic rights multilaterally. It attracted far fewer parties, and commercial rights came to be exchanged bilaterally instead.
Legacy
More than eight decades later, the Chicago Convention still governs. ICAO counts 193 member states. Every passport scanned at a gate, every runway marking, and every air traffic control phrase traces back to the framework agreed in Chicago.