WordNet (r) 3.0 (2006):

air lane
    n 1: a designated route followed by airplanes in flying from one
         airport to another [syn: air lane, flight path,
         airway, skyway]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "air lane":
   air line, air route, airway, beat, circuit, corridor, course,
   flight path, itinerary, lane, line, orbit, path, primrose path,
   road, round, route, run, sea lane, shortcut, tour, track,
   trade route, traject, trajectory, trajet, walk