One major advantage of using compressed air to power a car's engine is that a pure compressed air vehicle produces no pollution at the tailpipe. More specifically, the compressed air cars we're likely to see in the near future won't pollute at all until they reach speeds exceeding 35 miles per hour. That's when the car's internal air compressor will kick in to achieve extra speed. The motor that runs this air compressor will require fuel that'll produce a small amount of air pollution. Some fuel (you can use eco-friendly biofuels or fossil fuels) will also be used to heat the air as it emerges from the tank. The newest compressed air engines also offer drivers the option of using fossil fuels or biofuels to heat the air as it enters the engine. Nonetheless, this technology represents a marked improvement over cars powered by internal combustion engines that produce significant amounts of pollution at any speed.
Air cars are also designed to be lighter than conventional cars. The aluminum construction of these vehicles will keep their weight under 2,000 pounds (907 kilograms), which is essential to making these vehicles fuel efficient and will help them go faster for longer periods of time.
Another advantage of air cars is that the fuel should be remarkably cheap, an important consideration in this era of volatile gas prices. Some estimates say that the cars will get the equivalent of 106 miles (171 kilometers) per gallon, although compressed air will probably not be sold by the gallon. A more meaningful estimate is that it may take as little as $2 worth of electricity to fill the compressed air tank, though you'll also need gasoline to power the electric motor that compresses air while driving [source: Cornell].
The vehicles themselves also will be relatively cheap. Zero Pollution Motors, which plans to release the first air cars in the United States and estimates a sticker price of about $17,800, which would make these cars affordable to budget-conscious American buyers [source: Max].