The exemption refers to the vehicle's weight. The FAA decided to give the Transition a green light and allow a maximum takeoff weight (MTOW) of 1430 pounds (650 kg).
The new allowed weight is a bit over what the Transition used to weigh. According to Terrafugia, the increased weight is due to the addition of elements you would usually find in a car, but not in a plane.
Being both a car and a plane, the Transition needs to comply with two different sets of regulations. One, it has to meet the FAA rules and two, it also needs to comply with the Federal Motor Vehicle Safety Standards (FMVSS).
Whereas a plane doesn't need safety features like the airbags, an energy absorbing crumple zone, and a protective safety cage, a car does. It is exactly these elements which added to the weight of the aircraft.
The Transition is, as some of you might already know, a folding wings, light sport machine capable of both land and air travel. It is powered by a Rotax 912S engine, capable of giving the machine a range of 400 nautical miles (460 miles) at a top cruising speed of 100 kts (115 mph). For land use, the two-seater Transition uses a front wheel drive setup.
The Transition changes from plane to car in just 30 seconds and can soar 400 miles through the air on a single tank of gas, with a cruising speed of 115 mph. The vehicle has front wheel drive on the road and a propeller for flight but no matter the mode, it uses unleaded gasoline from a regular gas station.
Deliveries of the vehicle are expected to begin in 2011, for prices starting at $194,000.