Fuel cell technology is all the rage, and some say it might even revolutionize transportation. Boeing is bullish enough to begin designing a small fuel-cell-powered propeller plane. If its research bears fruit, there could be a place for fuel cells in jetliners too -- replacing the gas turbine auxiliary power units (APUs) built into the rear fuselages of jets.

The corporate jet has long been the ultimate status symbol, but Renaissance Research is out to challenge jet-powered primacy. The California-based company is bent on designing the fastest propeller plane in history and, ultimately, on producing an alternative to today's midsize jets.