Air cars and air engines

I've been following the development of the aircar at least since 1999.
They seem to be stuck (perhaps because of some big, evil conspiracy against them, or maybe just because their prototypes do not scale for real applicatons): too bad, I'd like a car like that :(

Anyway I just discovered that in Australia, someone (Angelo Di Pietro) has invented a different kind of air engine, piston-less, very small and light ... and fully working!
Take a look here.

Here is a nice movie clip, discussing the two concepts :)