Pinned at the front and back on a rotating axis down the centreline of the car, with the "car" itself being mostly lightweight composite with zero internal components other than the necessary air tanks and a large RC car motor to get it to roll up to the jump point? For the support structure, just put some dark matte scaffolding in the background so it stays out of shot and hidden by the light show. It wouldn't be too far off from standard wirework for movie stunts, and the compressed air could still do enough work to fool the eye. It's not like people have an innate sense for what a gas thruster powered flying car should look like anyway.

But you know, that's just off the top of my head.