Why do airplanes need a towing tractor (towbar-less tractor) even though they are able to move themselves under their own power?
Airplanes are parked at the airport facing the terminal building. They need to move to a taxiway for departure, but they cannot move in reverse. This is why a towing tractor needs to push the airplane. (Technically airplanes can go backwards using reverse thrust, however, in Japan, it is banned to use reverse thrust in the direction of buildings.)
A towing tractor is also used to move airplanes into a hangar after all the passengers and crew have left the aircraft. Instead of the pilot, a handling operator safely moves vacant airplanes using a towing tractor.