ORIGINAL: Gravityisnotmyfriend

I like the idea, but I think that ramp is a little harsh. If you hit that thing at 50mph, those Avistar wings will probably fold right down around the car. I would go with a longer ramp that didn't go vertical so quickly. Also, I would mount the wings with either a neutral incidence or even a little down. Meaning that when the car is sitting on the ground, the wings will either be paralell to the ground, or the front of the wing will be a little lower than the rear. This will keep the plane/car on the ground until after you hit the ramp. If it were me though, I would add an airplane engine to the top of the rig. Something in the 40 size that would really pull it along. Then, you could lighten up the car be removing the engine and fuel tank. You could rig up the rudder servo to steer it on the ground and that would eliminate all the heavy stuff on the car. You could probably eliminate one or even two of the wheels to lighten it up even more.... wait a minute, I think I already have one of these
Seriously though, it should work. I wouldn't worry about powering it in the air. If you launch it at 50, you should be able to get a pretty long flight. And, with all the suspension, you don't have to worry about hard landings.

-edit
I just got a crazy idea. Why not use a couple of y-harnesses and hook up the ailerons of the wing to the steering channel on your car? Then, hook up the elevator to the throttle channel (more throttle means up elevator, less throttle means down). It would be much of a plane, but you'd have a car that could "jump" a couple of hundred feet with a fairly small ramp. That way, you wouldn't have to try to communicate with a co-pilot. The only problems are
#1: I don't know if it would be considered flying and therefore need to be on a different frequency
#2: If you did hook up the car throttle to elevator, be careful about putting on the brakes - it would stop you REAL quick.