All your answers are here: http://en.wikipedia.org/wiki/Air_car
Aircar won't work very well because air storage, even at very high pressure (4000+ PSI), is not an efficient way of storing energy.
The only possible reason to use an Aircar is if it is very cheap to produce the drive train (engine & transmission; actually no transmission is needed) - but a conventional gasoline powered drive train is already fairly cheap to produce.
Aircar won't work very well because air storage, even at very high pressure (4000+ PSI), is not an efficient way of storing energy.
Using energy to compress air is less efficient than charging a battery with that same energy[8][9] - compressed-air car's overall efficiency is approximately one third of a comparable electric car.[10][11][12]
The only possible reason to use an Aircar is if it is very cheap to produce the drive train (engine & transmission; actually no transmission is needed) - but a conventional gasoline powered drive train is already fairly cheap to produce.