A method performed by an unmanned aerial vehicle, UAV (10), or a remote control (30) for the UAV, for executing an operating session for the UAV in controlled airspace, comprises the steps of transmitting a request for permission to operate in the airspace to an airspace authority function (20) and receiving a reply to the request. If permission to operate is granted, the following steps are performed: receiving a message comprising information about a space-time region of airspace to operate in, monitoring a position of the UAV in space and time, and, if the position of the UAV is within the region and the UAV is either within a predetermined distance from a geographical border of the region, or predicted to reach the geographical border of the region within a predetermined time, activating assisted control of the UAV to keep the UAV within the region.