Well, basically got a nice doll-car that I wanted to rework into a SHIELD car since it was about the right size, plus it was pretty much hollow so it can sit on a flying stand.
I replaced the axles with magnets that connect to either the side of the wheel or the center, so they could just be repositioned into flight mode. The little turbines in the wheels connect with magnets too. Thought that worked pretty well, without having to make some weighty mechanism. Always liked the flying cars.
Rogue