The sellers of an Aerocar are seeking $3.5 million US for the vehicle. ((eBay))

A 1956 Aerocar, the only vehicle to receive FAA certification for travel both in the skies and on the roads, has been put up for sale on the online auction site eBay.

The Colorado-based sellers are seeking $3.5 million US for the vehicle which was last inspected in July 1976. Only six Aerocars were ever made.

The cars were designed and manufactured by Moulton Taylor of Longview, Wash.

The plane has logged 1,103 flight hours and spent 303 hours on the roads, according to the auction description. When the tail wings are added to the car's central hub housing its 160 HP engine, the plane can reach speeds of up about 160 km/h.

The auction closes Dec. 16.