A lot of folks have been interested in Tata Motor's Air Car, the "OneCAT" also known as the "MiniCAT." Unfortunately, as of this writing, the car is unlikely to be produced any time soon due to challenges in getting it to run economically enough for the average buyer.
Nonetheless, interest remains strong. I found this neat video on you tube by CATvolution which gives a handy explanation of how a compressed air vehicle would work - straight from its inventor, Cyril Negre
http://www.youtube.com/watch?v=xakXvMl-r4w
Nick Aster is the founder of TriplePundit. Prior to launching 3p, Nick worked for Mother Jones magazine, successfully re-launching the magazine's online presence. He worked for TreeHugger.com, managing the technical side of the publication for 3 years, and has also been an active consultant for individuals and companies entering the world of micro-publishing. He also worked for Gawker Media and Moreover Technologies in the early days of blogging. Nick holds an MBA in sustainable management from the Presidio School of Management and graduated with a BA in History from Washington University in St. Louis.