I've looked into this one in the past too- fun to think about. Ultimately I'm skeptical because we don't see the type of artifacts we should. For example:
details about the mechanics and servicing of the vehicles
equations describing the properties
use of similar technology in peripheral applications (eg. In wheeled vehicles)
I've looked into this one in the past too- fun to think about. Ultimately I'm skeptical because we don't see the type of artifacts we should. For example: