Landing a plane is fairly trivial considering that autopilot simply guides the aircraft down a radio beam, cuts throttle and raises its nose a bit when on-board

Landing a plane is fairly trivial considering that autopilot simply guides the aircraft down a radio beam, cuts throttle and raises its nose a bit when on-board radio altimeter crosses below 50 feet. First fully automated landing in revenue service predates the first microprocessor, which should give an idea of the tech used. The difficult part is decision-making in non-standard situations like Sully landing on the Hudson with his A320.