eeldefineeritud piiridega õhuruumiosad, mille sees toimuv tegevus nõuab asjaomase õhuruumi reserveerimist etteantud ajaks teatud kasutajate tegevuseks., an airspace temporarily reserved and allocated for the specific use of a particular user during a determined period of time and through which other traffic may be allowed to transit under air traffic , a defined volume of airspace normally under the jurisdiction of one aviation authority and temporarily reserved, by common agreement, for the specific use by another aviation authority and through whi