OK, I learned how to get vids without having to link to that site. Here is a jet powered motorcycle. If I posted this on 1130cc.com Frank would probably see it and build one!
Here is a picture of some generic turbine powered APU. These are most commonly used for these projects as they come with a reduction gear to turn the turbines 20,000+ rpm into something usable.Read an interview once with Jay Leno about his jet bike. It is turbine driven, the engine coming from a jet helicopter. Takes awhile to spin up... but once going hold on tight! He learned early on to warn drivers behind him to not get too close... especially at stop lights. Guess some serious heat can shoot out the back, warping the front plastic on cars!
Turbine engines, by the physics involved, are much more fuel efficient at altitudes from 20,000 and up. Half of your atmosphere, by weight and somewhat directly then by density, is below 18,000 feet. Turbines can be developed to run better at sea level, but it is really a game of making the best of a bad situation. The tanks that Nate mentioned use HUGE amounts of fuel. But the engine package is so light that they can carry more fuel in the tank, and as there is nothing to be gained by keeping he engine idling like a diesel tank, they can turn it on and off basically at whim.And above and below?