This is the "RocAtomic" by General Motors, from the cover of the Sciences and Techniques For You" Magazine of 14 December 1947.
"Powered by atomic energy this vehicle has no wheels and floats a few centimeters above the road". Likely this design was from the
advertising and promotion department of either the magazine or General Motors. It is doubtful that there was ever any serious
developmental work done on this one.