 The Scaled Composites Proteus aircraft was flown as a surrogate UAV controlled remotely from the ground, although safety pilots were aboard to handle takeoff and landing and any potential emergencies.Three other aircraft, ranging from general aviation aircraft to a NASA F/A-18, served as "cooperative" target aircraft with an operating transponder.In each of 18 different scenarios, a Goodrich Skywatch HP Traffic Advisory System (TAS) on the Proteus detected approaching air traffic on potential collision courses, including several scenarios with two aircraft approaching from different directions.