The oldest surviving, original, fixed-wing roadable aircraft was designed Frank by Skroback in 1925 and built in 1934. It's now on display in Willowbrook Village in the north-eastern USA, near where he lived. Frank actually drove his invention along highways in Maine.
A total of six 8-ft.-long wing-segments provide the same wing area as one single 48-foot (16m) monoplane span - more than enough to lift a single occupant. Aerodynamically speaking, torque, induced drag and interference were the main issues facing Frank. It's unknown how he resolved these.