In 1949, engineer and former Navy pilot Moulton B. Taylor set about creating a practical and mass-produced flying car. Amazingly, he succeeded in designing a working model that could be converted from car to airplane in only five minutes by one person and received certification from the Civil Aeronautics Authority (now the FAA) for flight.

Unfortunately, the Aerocar, as Taylor named it, never received enough orders to justify production and it subsequently went the way of so many other cool things we'll never have. That is, unless you have $3.5 million and an eBay account.

Only six Aerocars were constructed, in three designs, all of which still exist. Three are in museums and three lie in private collections, only one of which still flies. Aerocar N103D, the third model built, hasn't flown since 1977, but remains in original condition and is currently being offered for sale as part of a divorce settlement.