The Transition, a plane that can also be driven as a car, won't come out for a few years, but you can try a flight simulator now and put a deposit on a future plane too.

Terrafugia, a "roadable aircraft" developer that emerged out of MIT, has devised a flight simulator for its aircraft (which can be downloaded here). The application runs on top of the X-Plane simulator for Laminar Research.

Potential buyers can also now plunk down $7,400, or 5 percent of the anticipated $148,000 purchase price, for a deposit on a Transition. The planes will come out in late 2009. A fully operational prototype is expected to come out in 2008.

Some third parties have already put deposits down, according to Anna Mracek, COO of Terrafugia. If you put a deposit down today, you would be reserving an airframe number between 20 and 30. (Some early airframes will go to planes sent to government agencies for testing.)

Although the term "flying car" makes for an easily graspable mental image, Terrafugia prefers to call it a roadable aircraft because the Transition will spend most of the time in the air. Owners will, ideally, drive the two-passenger vehicle from their garage to an airport. At that point, the retractable wings will be unfolded and it will turn into a plane.

Terrafugia showed off a 1/5th-scale model at the AirVentures Conference in August in Oshkosh, Wis.

"A few of the older gentlemen I talked to told me that they had been waiting for something like this their whole lives and were so excited that we were making it real while they were still able to fly it," wrote Mracek in an e-mail. "There was naturally some healthy skepticism as well, but even the skeptics were looking forward to us bringing a flying prototype to Oshkosh one of these years."

The model will be shown off again on Sept. 9 at the EAA Sport Pilot Tour at Lawrence Municipal Airport in Lawrence, Mass.

The Transition is designed for jumps of 100 to 500 miles. It will carry two people and luggage on a single tank of premium unleaded gas. It will also come with an electric calculator (to help fine-tune weight distribution), airbags, aerodynamic bumpers and, of course, a navigation unit with a global positioning system.

A couple of budding airlines and light-plane manufacturers say the future of commercial aviation lies in carrying passengers on small planes for relatively short hops. Roads are crowded, getting to the airport remains a chore, and major airlines don't conduct many flights between suburbs or outlying cities that have emerged as regional economic powers in the last two decades. Most of these planes, however, won't get driven to the airport like the Transition but get boarded at the airport.

A couple of other start-ups, some of which are still in stealth mode, are looking at recreational flying vehicles.

Flying cars are technically feasible. Terrafugia co-founder and CEO Carl Dietrich points out that inventor Molt Taylor built prototypes in the 1950s and 1960s--but they haven't been economically practical.

The picture has changed, however, with the development of lighter and stronger construction materials and more-efficient engines.

Dietrich came up with the idea while a student at MIT's Department of Aeronautics and Astronautics. Earlier this year he won the Lemelson-MIT Prize, which recognizes invention and innovation. He also holds a patent for the centrifugal direct injection engine, a low-cost, high-performance rocket propulsion engine. Dietrich conducted his rocket engine research as an undergraduate at MIT.

im still not convinced

We should prepare for a major increase in deaths.

doubt it. If people can navigate traffic in Seattle during rush hour they'll be fine in an empty sky