while it's an interesting concept, there is absolutely nothing that makes it attractive. it's not going to be great plane and it's not a good car. it doesn't share any components. the only thing is maybe sharing the chassis/fuse.

if you really want to see this thing fly. take an avistar, add one pound of weight. fly it. if it flies fine, add another pound. if it still flies (it should since you'll only have about warbird wingloading then anyway) then take the avistar and strap it on the the car and drive it off the cliff. should work like a charm.

if you want to be sophisticated, then try to leverage components. for example, if you're running shaft driven car, try to add a pully to pull a prop rather than using an additional powerplant. better yet, instead of driving all four wheels, lift the front gear box higher and run a prop. if you're using a belt driving car, consider disengaging the front drive and routing that to a prop on top of the wing.

otherwise, string up a whole bunch of zip ties and just lash that car on the belly of the avistar... of course, watch out for the CG. i don't think it will be that hard.

what about putting a parachute on the car and dropping from 1000ft?

oh yeah.. and whatever you do, video please!!!