This chapter focuses on commercial passenger aviation, although many of the points made may be applicable to other types of aircraft operations. One interesting aspect of International Civil Aviation Organization's (ICAO) working definition of ‘autonomy’ is that so long as the aircraft is capable of human intervention, it is not ‘autonomous’ and therefore would be acceptable to the ICAO regime and could be automated to an extremely high degree. The pilot plays a central role in the civil international air traffic system, as described by the ICAO. Nations agree to conform to ICAO’s publications and thereby are able to participate in the international civil aviation sector. New information technology systems, which allow all aircraft to have a common operational picture of all the aircraft around them, combined with collision avoidance systems and digital communications with air traffic control all contribute to the future possibility of safe automatic aircraft in flight.