Why you could soon own a flying car.

What a difference getting airborne makes. Until this month, flying cars were the stuff of Blade Runner, postmillennial defeatist humor about how far we haven't come since the Futurama era, and, of course, TV spots. "Where are the flying cars? I was promised flying cars!" declaimed actor Avery Books in a 2000 ad for IBM that concluded we really don't need them because we have the Internet. Ah, 2000. We were so innocent then.

Everything changed on March 5, when the Terrafugia Transition took to the skies. You can watch it taxi along a runway in Plattsburgh, N.Y., and achieve liftoff here. Yet this isn't your father's flying car. The Transition is a departure from the gee-whiz, futuristic air chariots of yore. In fact, it really isn't a flying car. It's a "roadable aircraft," a plane that drives rather than a car that flies. And it comes complete with a viable business plan, which is unsurprising, given that it was developed by a 32-year-old MIT wunderkind engineer and some tech-savvy MBAs and has so far attracted several rounds of investment. Although the Transition still has to undergo plenty of testing to satisfy various safety requirements, Terrafugia is taking deposits.

By flipping the flying-car fantasy to place the emphasis on fly rather than car, Terrafugia isn't aiming at customers who mostly drive but dream of flight. Rather, it's looking to bring the option of driving to those who fly, thereby offering a less expensive yet more versatile type of general aviation. The Transition's predicted price tag will be near $200,000, and although that's steep by car standards, it's a bargain in the new small-plane market. And while there are some other, older flying car designs out there—not to mention at least one competitor for Terrafugia's folding-wing concept—Terrafugia has gotten there the firstest with the mostest. It helps that they take the potential business seriously and have the talent to give their flying car a plausible destiny. The more you think about it, the more the Transition seems practical rather than an exotic toy.

For starters, the Transition opens up an underused component of the national transportation grid: small regional airfields. Commercial flight on the big birds is focused on hub systems and excludes airports that lack the long runways jumbo jets need for takeoff and landing. Private jets can go in and out of smaller fields, but the price of entry is high, even if you only go the fractional-ownership route. Buying a small single-engine, prop-driven plane isn't exactly cheap—more than a quarter of a million bucks new is typical, and that's before you figure in all the added costs, like fuel and hangaring and the lessons you need to fly it. And once you get where you're going, if you don't have a car or other form of earthbound transport waiting, you're walking, because most smaller airfields lack access to rental cars and taxis.

Regional airfields are like islands in the transportation ocean, and there are thousands of them. The Transition can zip in and out either by air or on the ground. Massive range is unnecessary because the Transition can always land and refuel, and its versatility means that trips can be made door-to-door. Apart from the wings, which can fold up in 30 seconds, nothing here is particularly esoteric. It runs on regular gas and uses the same engine to drive the prop and the wheels. The Transition wants to make island-hopping an option.

It's easy to imagine early adopters in Silicon Valley lining up in droves to plunk down deposits on the Transition's initial limited production—there's really no conversational substitute for saying you have a flying car parked in the garage. I'd be shocked if both Dean Kamen and Elon Musk aren't already on the list. But you can also imagine a more pragmatic customer for the Transition—and if the company is going to succeed beyond being the cool new toy, it needs to. A winemaker or vineyard manager with holdings spread out over the state of California would be ideal, as would anyone who needs to deal with a large geographical area where the roads are of reasonable quality. A "roadable aircraft" that can be driven to the airfield, flown a few hundred miles, then driven out to the vines—and gassed up at a Chevron station—would enable this person to cover his territory in a day or two, without having to arrange pickups and drop-offs along the way. Nor would bad weather be an issue; the Transition would simply land and drive through.