Popular Mechanics has an article (http://www.popularmechanics.com/automotive/new_cars/4251491.html?series=19) about a new car coming to the States next year that runs on air.  The air tank powers the car up to 35 Mph (56 Kph) and a gas powered engine kicks in above that to top out at 96 Mph (154 Kph).  The car is expected to go about 1000 miles on a single fill (1609 km).