the part of the sky where planes fly, usually the part above a particular country that is legally controlled by that country The airspace over Europe is becoming more and more crowded. The jet entered Chinese airspace without permission. See related entries: Plane travel, SkyExtra examples The jet had crossed into Russian airspace. The president said that all future violations of our airspace would result in serious consequences. They have decided to open their airspace to commercial aircraft. They were now out of controlled airspace.