A new carmaker has a plan for cheap, environmentally-friendly cars an air-powered car. It may be available sooner at a price tag that will hardly be a budget buster. The vehicle may not run like a speed racer on back road highways, but developer Zero Pollution Motors is betting consumers will be willing to fork over $20,000 for a vehicle that can motor around all day on nothing but air and a splash of salad oil, alcohol or possibly a pint of gasoline.