Popular Mechanics did an article about this air powered car. They have some models ready for production, but they’re 2 and 3 seaters. The picture is the concept for the 6 seater.
The theory is that it uses compressed air to get the vehicle up to 35 mph, and then a more standard combustion engine takes over. They’re looking at gasoline, bio-deisel and ethanol for the combustion engine.
The estimates are that it should be able to travel at 96 mph for 800-1000 miles on about 8 gallons of fuel.