A collision avoidance system including a receiver configured to receive navigational data regarding intruding aerial vehicle and own aircraft. Storage is configured to store a plurality of predefined escape trajectories. A processor is configured to compare at least a subset of the predefined escape trajectories with a presumed trajectory of the intruding aerial vehicle and to select one of the predefined escape trajectories based on the comparison. The predefined escape trajectories are pre-simulated, wherein each escape trajectory is associated to a set of navigational data and to an escape maneuver direction.