Air-powered cars..... attn PV if he's still around.

Not way too long ago in China, they had city buses with big bags on top
of those buses.They had natural gas inside of those bags for the bus
engines to run on.They could go about thirty miles.I once read about
that in a National Geographic magazine.

Switzerland had some flywheel powered city buses.At some of the bus
stops, a cantilever arm would reach up and make contact with some
electric wires, sort of like old fashioned trolley cars.That would rev
up an electric motor which reved up the flywheel in the buses.
cuhulin