The auto industry has seen its share of technological leaps, whether it was the advent of electric starters, automatic transmissions or hybrid gas-electric powertrains. And don't forget hideaway headlights.
One leap that engineers and tinkerers have never quite made, however, but refuse to let die: the flying car.
Year after year a few more try. Of all those stuck stewing in traffic gridlock, who hasn't imagined soaring Jetsons-style directly to a destination?
Most flying cars never get off the page, let alone the ground. The few that do are bedeviled by lack of funding, impracticality, limited appeal or fears they may simply break apart in flight — as some have.
The fact is that these keystones of modern transportation — cars and planes — have basic differences that make them a match made in hell.
"It's like trying to mate a pig and an elephant," says Lionel Salisbury, editor of the Roadable Times, a website that has made him a de facto chronicler of flying car attempts. "You don't get a very good elephant, or a very good pig."
Today, a new crop of magnificent men and women believe advanced materials and sounder business practices finally will allow their flying machines to defy skeptics.
They range from a guy who just built a prototype three-wheel flying motorcycle in the driveway of his Los Angeles home to a Woburn, Mass., company with more than 50 orders for a two-seat car that flies. Some designs call for wings that telescope. Some fold, manually or at the push of a button.
No dreamers allowed. Only cold-eyed realists. Aware of how quickly they can be branded kooks, the new breed deliberately discourages the label "flying cars" and eschews Hollywood fantasies such as Harrison Ford cruising the skies of Los Angeles in Ridley Scott's 1982 Blade Runner.
Their preferred terminology is "roadable aircraft" — a plane you can drive to the airport, then sprout wings and fly off into the sunset. They see early adopters as private pilots.
"You get a lot of people who have the Jetsons dream of one of these things in everyone's driveway. Maybe that will happen someday, but it's not something you can build a business on now," says Carl Dietrich, CEO of Massachusetts-based Terrafugia.
The effort has been helped by innovations in cheap, lightweight engines and strong, light materials such as carbon-fiber composites. They could finally lead to an affordable vehicle equally at home on the interstate or the runway.
Today's group follows pioneers such as Paul Moller, who has pursued his vision of a flying car since 1970. He predicted to USA TODAY in 1994 that he would be mass producing his M400 Skycar by 2000 and selling it for as little as $30,000. His company is still alive — and he's still trying to start production.
Moller was far from the first. Salisbury, a former pilot living north of Toronto, says he's found records of attempts at a flying car formulated "within months of the Wright brothers." The first patent was issued 15 years later in 1918.
At least 100 serious tries followed. The original Aerocar of the 1950s was among the most successful, with five built, says Jake Schultz, author of A Drive in the Clouds — The Story of the Aerocar. It was a novel design: The wings detached to turn into a trailer towed behind the car. He says at least one is still flying and three are in museums.