If i were you, I would make it where the car is attatched on the plane with a quick release,and make a 2 way switch where you can drop the car, yet on landing, you can attach back onto the car. So the car would be like a rope and hook on landing. Something like this

Takeoff, get as high as possible and detatch car, come in on approach, (have a mietal bar or something to latch easily too on landing) and hook on while the car is moving. That just sounds awsome