Modern-Aviation

Convair 103 (1944)
George G Spratt (1904-1998) and William Bushnell Stout (1880-1956) clubbed together to come up with this confection; the Convair 103 which confusingly was also known as the Skycar IV or Spratt-Stout Model 8. Despite having three names just one example was built and it worked fine, but it was more of a plane that could be used on the road rather than a car that could fly.

Fulton Airphibian (1946)
Robert Edison Fulton Jr (1909-2004) made his fortune during WW2 with a flight-and-combat simulator and when hostilities ended he decided that what the world needed was a car that could fly. The Airphibian was the result; a fuselage without wings, to which a rear section complete with wings could be attached. It was claimed to take just seven minutes to convert from car to plane and just four minutes to switch back. The first flying car to be approved by US authorities, the investors pulled out once 11 Airphibians had been built in the early 1950s – and the project collapsed.

ConVairCar Model 118 (1947)
Theodore P "Ted" Hall (1898-1978) planned to make 160,000 examples of his Convair but didn't quite manage it; just two were built. He created a car which drove underneath a 'flight module' which attached to the car with its own engine and propeller.
The plan was to sell them at $1500 apiece but when one of the prototypes ran out of fuel and crashed on a routine test flight, killing the pilot, the plug was pulled and by 1949 it was all over.

Taylor Aerocar (1949)
One of the best-known flying cars even though it surfaced decades ago, Moulton Taylor (1912-1995) hoped to put his Aerocar into full-scale production. It came pretty close too, with five airworthy examples produced before the project fell apart.