A method for coordinating drones flying in a divided airspace that includes sending patrol instructions to each drone of a set of airborne drones in a divided airspace, where the divided airspace includes mutually exclusive horizontal layers having a ceiling altitude and a floor altitude and at least one transition space layer, where the layers comprise sectors, where the patrol instructions direct the drone into a flight path in a sector, sending first transition instructions to a first drone, where the transition instructions direct the first drone to move from its sector to a transition space layer and from the transition space layer to exit the divided airspace, sending second transition instructions to a second drone, where the second transition instructions direct the second drone to move from outside the divided airspace to a transition space layer and from the transition space layer to the sector of the first drone.