With regards to airplanes, you have several issues. The main one being that airplanes are not equipped with sensors capable of detecting other aircraft nearby. Without a complete picture of the airspace to a very significant distance a fully autonomous aircraft isn't possible. Today that is managed by the air traffic control system which is entirely run by people communicating with other people. That said, aircraft are capable of fully autonomous landings - https://en.wikipedia.org/wiki/Autoland.