The PAL-V, or personal air and land vehicle, would drive like a car, take off like a plane, and fly like a gyrocopter. Drawn up by a Dutch firm called Spark Design Engineering, the PAL-V would feature a foldaway rotor and propeller, and a 213-horsepower engine that runs on regular.

But don't get ready to make a down payment just yet. The designers are still waiting for the funding to build a prototype, but they say it would be easy for the average driver to handle, and would fall under the FAA's sport pilot certification category, which means potential owners wouldn't need endless hours of training to operate it legally.

IEEE Spectrum, which reviews the design in a recent issue, suggests that this flying trike, which first turned up a few years, may not get off the ground.—Gregory Mone

The Vandenbrink Carver is a crossover vehicle of a different sort: Its enclosed cabin is reminiscent of a car's (specifically, the New Beetle's), but it seats just two-a driver and a petite passenger-in tandem like a motorcycle. It leans into turns (motorcycle), a motion controlled by the steering wheel and not the weight of a driver (car). Its three wheels split the difference.

Our test location couldn't have been more fitting -- barely 30 minutes south of San Francisco's international airport, right along the coast in a tiny hamlet called Half Moon Bay. You can be in downtown San Francisco in less than an hour from here, yet -- as we put the all-new Lexus ES 300 through its paces on curvy two-lane roads -- I notice a surprising lack of cars on the road. Not what I expected from suburban San Francisco.