1. In the U.S. Air Force, an establishment, comprising an airfield, its installations, facilities, personnel, and activities, for the flight operation, maintenance, and supply of aircraft and air organizations.

2. A similar establishment belonging to any other air force.

3. In a restricted sense, only the physical installation.

1. The line joining two air stations, or the length of this line.

2. The distance, at the scale of the stereoscopic model, between adjacent perspective centers as reconstructed in the plotting instrument.