What happened to the AIR car?

''In 2008, India’s largest car manufacturer announced that it would begin production of world’s first commercial vehicle to run on nothing but a puff of air — compressed air, that is.

The Air Car concept, developed by the French company Motor Development International (MDI) in partnership with Indian giant Tata Motors, would have used compressed air, as opposed to the gas-and-oxygen explosions of internal-combustion models, to push its engine’s pistons.

The car was said to achieve speeds of up to 68 mph with a range of 125 miles between fill-ups, all for less than $13,000.
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Although the Tata version of the zero-emissions car might never make it into commercial production, a more credible version is currently being developed by a duo of mechanical engineering professors in India.'' [source, more here]

A working air engine!
''Angelo Di Pietro is an Italian engine designer who once worked for Mercedes Benz on their Wankel Rotary engine in 1969-1970, then migrated to Australia to pursue other interests, among them, as hobbyist / inventor of the Di Pietro Rotary Air Engine.
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This very efficient, effective, non-reciprocating configuration allows the air engine to be very small and compact, yet very powerful. Any car guy worth his salt should recognize that this combination of high power and small size / weight translates into a great application for personal transportation. To that end, Di Pietro has adapted his air motor to carriers for produce markets, ATV load carriers, scooters and even boats (shown).'' [source]