"Pentagon Wants Kill Switch for Planes"
By Noah Shachtman

"The Pentagon's non-lethal weapons division is looking for technologies
that could "disable" aircraft, before they can take off from a runway -- or
block the planes from flying over a given city of stretch of land.
[...]
it would like arms-makers to come up with a way to "safely divert an
aircraft in the air or stop and/or disable an aircraft on the ground." And
no, shooting the thing with a missile doesn't count."

Complete article (which includes a link to the request for proposal) here":

http://blog.wired.com/defense/2008/0...ntagons-n.html

I wonder how they'll disable gliders, sailboats, and rowboats?