Zero Pollution Motors of New Paltz, N.Y., has obtained a license from MDI of Barcelona, Spain, to produce the six-seat "air cars" in the United States, which is says it will begin delivering for less than $18,000 in 2010, CNN reported Saturday.

Shiva Vencat, vice president of MDI and CEO of Zero Pollution Motors, says the cars use compressed air in much the same way old locomotives used steam to power engine pistons. He told the broadcaster that one or more tanks of air under the car's floor would work in tandem with an 8-gallon gasoline tank to produce fuel efficiency ratings of up to 106 miles per gallon.

But some doubt its feasibility. John Callister of Cornell University noted that such fuel efficiencies are associated with tiny experimental cars, not bigger mainstream ones.

And William Bulpitt of the Georgia Institute of Technology told CNN that the compression needed for the air tanks would have to be very high for them to power a car engine.