WordNet (r) 3.0 (2006):

air space
    n 1: the space in the atmosphere immediately above the earth
         [syn: airspace, air space]

Moby Thesaurus II by Grady Ward, 1.0:

97 Moby Thesaurus words for "air space":
   CAT, Lebensraum, aerospace, aerosphere, air hole, air pocket, area,
   back country, belt, bump, ceiling, clear space, clearance,
   clearing, confines, continental shelf, corridor, country,
   crosswind, department, desert, distant prospect, district,
   division, elbowroom, empty space, empty view, environs,
   favorable wind, fog, front, glade, ground, head wind, headroom,
   heartland, high-pressure area, hinterland, hole, ionosphere,
   jetstream, land, latitude, leeway, living space, low-pressure area,
   margin, milieu, neighborhood, offshore rights, open country,
   open space, outback, overcast, part, parts, place, plain, play,
   pocket, prairie, precincts, premises, purlieus, quarter, region,
   room, room to spare, roughness, salient, sea room, section, soil,
   soup, space, spare room, steppe, stratosphere, substratosphere,
   swing, tail wind, terrain, territory, three-mile limit, tropopause,
   troposphere, trough, turbulence, twelve-mile limit, vicinage,
   vicinity, visibility, visibility zero, way, wide-open spaces,
   wilderness, zone