The idea of a flying car is gaining traction, and this latest attempt is more akin to a flying tricycle with a helicopter rotor on top. The PAL-V is a three-wheeled gyrocopter concept whose blades fold up onto its roof, and when it's time to fly, its back end morphs into a U-shaped tail with a prop on the back and a gyrocopter blade up top.

Besides the challenge of creating a dual-purpose vehicle that can fly and drive, this a helicopter, tech that's been called "10,000 rattling parts flying in close formation." Undaunted, the PAL-V's inventors think this configuration is best because it's narrow, and they say such designs are better for flying into the wild blue. But what about on the road? They'll build in special tilting technology that can help the three-wheeler lean into the curves.

Will it ever become a reality? The PAL-V's confident creators are about to begin building a working prototype to prove it, and plan to launch the real thing in 2009 at an undisclosed price. Still, the idea of lots of people freely flying these vehicles at heights up to 4,000 feet is a frightening prospect.