Gas air compressor or gasoline powered air compressors are those mentioned that require gasoline in the small generator-like component of the machine. The fuel (in this case gasoline) is burned much like those on car engines and the combustion produces energy which is then converted into mechanical energy that turns the rotors, fans, vanes etc. inward the machine, locks the air passageway (thus trapping the air), and finally accumulating and storing the air, decreasing its volume and increasing the pressure within the tank.
Gas air compressors come in handy most especially during power interruptions, on a construction site or when a gas air compressor is needed because electricity access is either not available or insufficient.
The down side about this is that gasoline can become really expensive and would largely depend on the economic supply and demand.
When prices for gasoline rises, so does the cost of operation. Another problem is that you cannot simply store gasoline in containers because these materials tend to evaporate quickly and easily.
Gas compressors tend to be smaller and portable for home and small business use. Larger compressors that companies use when fuel is needed tend to be driven by diesel power. Diesel is a more stable fuel and common among towable and trailer mounted units.