On Monday, plans for the Terrafugia Transition, the latest consumer-model flying car, were unveiled to the public. The vehicle, which was recently given a 110-pound weight exemption by the FAA, transforms from a two-wheel drive car to an airplane with a range of 460 miles in less than 30 seconds. This latest attempt at creating a flying car available for the public has a few novel approaches: It incorporates airbags, bumpers and all of the required safety features of a normal car, and it is classified as a light sport aircraft, arguably the easiest class of plane to learn how to fly. However, no matter how cutting-edge the idea may seem, the concept of a convertible car-plane is almost 70 years old. Since the 1940s engineers have tried to combine aviation and automotive technologies for the consumer market, but none have been successful. It's not for a lack of innovation—there's a perfect storm of design problems, including the engineering give-and-take between car and plane, increasing safety regulations for both modes of transport and a lack of infrastructure that makes it hard to market to a niche clientele. The failures of past flying cars can teach Terrafugia a lesson—and may be key to its success.

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Bow to the Mechanical Reality

First of all, it is important to distinguish convertible car-planes from the speedy, levitating vehicles seen on the Jetsons and in the movies. The FAA designates vehicles like the Transition as roadable planes, which are first and foremost aircrafts, but then also have the capability to be driven on the road. Don't expect to fly out of your house with these. While they can be stored in a home garage, they still require an airport runway to take off.

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In the past, roadable plane designs have been most limited by the challenge of merging two technologies into one craft. Nowhere else do car transmissions and airplane propellers operate on the same engine. The Aerocar, designed by Moulton Taylor, was one of the more successful marriages of these different technologies. The Civilian Aeronautics Association, the predecessor of the FAA, approved this two-seater vehicle with a top speed of 110 miles per hour in the air in 1956 for use by private pilots. After a flight, the pilot could manually fold back the wings against the body, or trailer them behind the car.

Even though it was functional as both a basic car and plane, the Aerocar, like most other flying-car designs, had its mechanical shortcomings. As an aircraft it was overweight and underpowered, and as a car it could not compete with the powerful American-made cars of the day. "Yes, it flew, but it didn't have the range, it didn't have the altitude, it didn't have some of the amenities that a normal airplane would have—so it kind of was a drawback," says Alan Westby, director of the AirVenture museum in Wisconsin.

Taylor, whose previous work included developing the first cruise missile, thought his Aerocar would bring aviation to masses. "He was absolutely fascinated with creating roadable planes, the everyman kind of vehicle," Westby says. Despite generating a lot of attention, Taylor could not collect enough down payments, and the project's investors dropped out. Only four prototype models were ever built.

Find the Market

The Fulton Airphibian, the first flying car to be approved by the CAA in 1950, also never sold a model, and for many of the same reasons. The vehicle, while being the first to successfully convert from a car to a plane, could only go 55 miles per hour on the road and could barely top 100 in the sky. In addition to the mechanical shortcomings, it was hard to market. It suffered from a cumbersome conversion process, and its detachable wings and propeller had to be left at the airport. Simply put, it was still more convenient to have both a car and a plane.

In the 1970s, a persistent Taylor attempted to market a third version of the Aerocar, (he built a second version, but it was not designed for road travel) which Frank A. Tinker, a writer for Popular Mechanics , found surprisingly stable in the sky. But even with improved mechanics and retractable wheels, this model also never made it to market.

The Aerocar III's failure was not so much due to engineering issues, but increasing government safety standards that kept it grounded. "It's a particularly difficult road to not only meet all the aircraft regulations, but to also meet the current automotive regulations," say Jake Schultz, author of A Drive in the Clouds: The Story of the Aerocar. In 1972, automotive safety regulations were more becoming stringent. Cars had to comply with bumper, side impact and crumple zone requirements, while airplanes had their own requirements. To satisfy both would have resulted in an aircraft that was just too heavy—a problem the Terrafugia has narrowly avoided. The Aerocar III would never be more than experimental aircraft, and Taylor would lay the idea to rest.

PM first featured a concept of the roadable airplane in 1942, calling the idea "10 years ahead of it time" and speculating that post-World War Two transportation would rely on the concept. However, 68 years later, there probably is not much more of a market for the flying car today then there was then. The ideal candidate for a flying car is very wealthy (the Terrafugia costs $194,000), has a pilot's license and has access to a runway—hardly a description of the everyman. "It's probably always going to be a novelty," Westby says.

Today's Reality: More Flying-Car-Friendly Than Ever

But maybe the Terrafugia has a chance. Today it enters a different, friendlier climate for the flying car. For one, it has become easier than ever to learn how to fly. In 2004, the FAA created the sport pilot's license in an effort to bring aviation to a broader population. Although sport pilots are restricted to flying light sport crafts—small propeller-driven planes like the Transition—and can only fly in daylight, they can be certified with only 20 hours in the air. In comparison, a private pilot's license, which allows a person to fly any non-commercial plane, takes at least 40 hours of flying and has requirements for night training and cross-country flights. Still, legal difficulties await the Terrafugia; the FAA has yet to clear a working consumer model of the plane.

The enduring allure of the flying car is the freedom it invokes, Shultz says, and that is why the concept has persisted in the face of many failures. Many white-knuckled motorists still look to the sky when they are bumper to bumper on our nation's highways, dreaming they could take to the sky. The Transition will probably be the best rendition of the flying car to date, but we are still many years away from commuting to work via sky.

What do you think?