Anair corridor was an artificial environment which could be extended into openspace. It provided a limited amount of protection to those who in it.The Doctor's TARDIS could create an air corridor and did so forRiver Song's escape from theByzantium spaceship for her to reach the TARDIS safely. (TV:The Time of Angels) Air corridors could sometimes be combined withforce fields andanti-gravity technology to allow people to walk, rather than float, through them. (TV:The Horns of Nimon)