One thing that makes flying faster is that most geological obstacles have no effect on your route. you need no roads (other than a runway) or tracks. you can go over lakes and rivers and most mountains (depending on your aircraft). So even if the speed was the same the aircraft is likely to arrive at the destination sooner. Unless you are to drive up to your friends house and he doesn’t have a runway or a place for your chopper. But he is unlikely to have railroad tracks either.