In the discussions of "GEFS Online" flight simulator, Jorg Buchholz mentioned that he had built a jetpack simulator in Google Earth. While the product isn't as polished as GEFS, it's still quite a lot of fun to play with!
By default you start in Christchurch, New Zealand, though you can quickly jump to any location in the world. Your jetpack hovers in the air, and you can control it using your mouse, keyboard or joystick. The controls and physics seem quite solid, though I don't have any first-hand jetpack experience. :)
If you use the keyboard, or likely with a joystick as well, the simulator supports simultaneous commands. For example, you can hold "8" and "1" to fly forward and up at the same time. It's a little thing, but adds quite a bit to the realism. This is a big reason why I enjoy using the SpaceNavigator with Google Earth -- you can be moving in a few different directions at the same time.
This is a fun little simulator and it's a neat way to explore your favorite cities. You can try it for yourself at jetpacksimulator.tk. Nice work, Jorg!