The Terrafugia Transition is an airplane which can drive on the road like a car. They call this a roadable aircraft. On the road at highway speeds it only uses 3.33 GPHM, which is pretty good. That good fuel economy is due to the aerodynamic streamlining required to fly coupled with the low weight also necessary for an airplane. In flight it burns 5 gallons per hour (airplane fuel usage is given in terms of volume per time, not volume per distance because the ground track speed depends on wind) at a cruise speed of 115 miles per hour. Flying in still air, it thus uses 5 gallons per 115 miles, or about 4.35 GPHM. Even flying, the fuel usage is better than for a typical SUV! Considering that flight allows for some impressive distance saving (straight line shortcuts) via route selection, the Transition could represent more than the futuristic flying car made real. It could actually save on gas!