Alternate Fuel Vehicles

--- In spacesettlers, "John Frazer" wrote:

> (No, neither the SSPS power beams nor the aircraft beams can
> be taken over by terrorists of militaries to burn cities. The SSPS
> beam is less powerful than sunlight in a frequency which can't
> hurt an airplane or bird, and the airplane power beams can't be
> focussed at anything below 30,000 feet.)

Good bit of anticipation. This question was bound to be asked. I
would recommend also that a bit of fuel be kept on board, even though
that would hurt efficiency. Just in case the beam is cut off
(military, terrorist, asteroid, debris, etc.).