air-space n.

c. 1300, "invisible gases that surround the earth," from Old French air "atmosphere, breeze, weather" (12c.), from Latin aer "air, lower atmosphere, sky," from Greek aēr (genitive aeros) "mist, haze, clouds," later "atmosphere" (perhaps related to aenai "to blow, breathe"), which is of unknown origin. It is possibly from a PIE *awer- and thus related to aeirein "to raise" and arteria "windpipe, artery" (see aorta) on notion of "lifting, suspended, that which rises," but this has phonetic difficulties.

In Homer mostly "thick air, mist;" later "air" as one of the four elements. Words for "air" in Indo-European languages tend to be associated with wind, brightness, sky. In English, air replaced native lyft, luft (see loft (n.)). In old chemistry, air (with a qualifying adjective) was used of any gas.

To be in the air "in general awareness" is from 1875; up in the air "uncertain, doubtful" is from 1752. To build castles in the air "entertain visionary schemes that have no practical foundation" is from 1590s (in 17c. English had airmonger "one preoccupied with visionary projects"). Broadcasting sense (as in on the air, airplay) is by 1927. To give (someone) the air "dismiss" is from 1900. Air pollution is attested by 1870. Air guitar is by 1983. Air traffic controller is from 1956.

c. 1300, "extent or area; room" (to do something), a shortening of Old French espace "period of time, distance, interval" (12c.), from Latin spatium "room, area, distance, stretch of time," a word of unknown origin (also source of Spanish espacio, Italian spazio).

From early 14c. as "a place," also "amount or extent of time." From mid-14c. as "distance, interval of space;" from late 14c. as "ground, land, territory; extension in three dimensions; distance between two or more points." From early 15c. as "size, bulk," also "an assigned position." Typographical sense is attested from 1670s (typewriter space-bar is from 1876, earlier space-key, 1860).

Astronomical sense of "stellar depths, immense emptiness between the worlds" is by 1723, perhaps as early as "Paradise Lost" (1667), common from 1890s. Space age is attested from 1946. Many compounds first appeared in science fiction and speculative writing, such as spaceship (1894, "A Journey in Other Worlds," John Jacob Astor); spacecraft (1928, Popular Science); space travel (1931); space station (1936, "Rockets Through Space"); spaceman (1942, Thrilling Wonder Stories). Space race attested from 1959. Space shuttle attested by 1970.

Space isn't remote at all. It's only an hour's drive away if your car could go straight upwards. [Sir Fred Hoyle, London Observer, 1979]