Bob Fulton sold out to GM who gave him a massive workshop and lots of money to NOT develop the aircar.
He civilianised Mustang N3333E and created the hybrid Merlin engine in the aircraft using a combination of Packard military and Rolls civil engine parts. When it ended up on its nose at Chino because a moron in a Cessna taxied in front of it while Dave was doing his engine runup Bob came and helped do the engine inspection. Great bloke.