1. An agreement between two or more countries to allow each country's airlines unrestricted access to the other country's airports and routes. The USA and Canada have such an agreement, as do the states of the European Union.
  2. Arms control treaty proposed by President Dwight D. Eisenhower in 1958 and finally signed on March 24, 1992. It allows signatories to conduct aerial overflights of each other's territory to check for weapons of mass destruction. Participating nations include Russia, Belarus, Ukraine, Georgia, France, the United Kingdom, and the United States.