I think the difference is the time delay afterward. You drive around, then return to your base before you start tracking. Or you have to check your game camera, then start tracking. With flying, because of the speed of the plane, you can be back to the airport and in your vehicle within a few minutes. It stretches the concept of "fair chase," and some state just plain outlaw it. There is also the issue of "driving" game. You can push game with a plane. Not so easy with a vehicle and essentially impossible with a camera.