If water powered cars aren’t good enough for you, you should check out this French air powered car. It works by expanding air. It does require an outside powersource to compress the air in the first place, but it’s highly effecient. The car will most likely be used for taxi businesses outside the United States.
Link (via Street Tech).

Another sign that the future is (finally) coming: Moller International has invented a flying car. Link (via Boing Boing).