Air transport agreement
A air transport agreement (also sometimes called an air service agreement or ATA or ASA) is an agreement which two nations sign to allow international commercial air transport services between their territories.
The bilateral system has its basis under the Chicago convention and associated multilateral treaties. The Chicago Convention was signed in December 1944 and has governed international air services since then. the convention also has a range of annexes covering issues such as aviation security, safety oversight, air worthiness, navigation, environmental protection and facilitation (expediting and departure at airports).