Air Powered Cars? Diving Related?

Air powered cars? Spooky
I read this a while back on Popular Mechanics while researching alternative energy methods for my ‘real job’ and thought the idea was ‘out there’.
Now another blog I visit posted this article from Forbes Magazine

The engine runs on air compressed to just over 4000 psi. Each car has an on-board compressor; however, a fill-up takes four hours. The Forbes article laments, “The car’s limited range would require plenty of fill-ups at compressed-air service stations, except those don’t exist.”

OK so how is this related to diving? Instead of having a spare gas can in the trunk you would now have a spare aluminum 80 scuba tank in the trunk as a ‘spare air’ (pun intended)