That's right, it runs on air. Specifically, compressed air. It's tank holds 90 cubic meters (3178 cubic feet) of compressed air. This allows the car to drive at speeds up to 68MPH, for up to 10 hours or 200-300km (125-186mi). An electric air compressor can refill the tank in about 3-4 hours.
The manufacturer expects filling stations to eventually start offering air-refill services. These stations would have high-pressure compressors capable of filling a tank in a few minutes. They estimate that a refill will cost about €1.5 (about $2). (Of course, that doesn't count the inevitable taxes that governments will impose to offset losses from gas-tax revenues if people stop burning gasoline in their cars.)
In terms of scheduled maintenance, it needs an oil change (1l of vegetable oil) every 50,000km (or one quart every 31,000mi).
It's exhaust is just air. Interestingly enough, this exhaust is very cold air (below freezing temperatures), so the car can recirculate it as a part of the air conditioning system.
The manufacturer expect a selling price of £5,500 (about $9,000).