http://www.cnn.com/2004/TECH/science/08/02/directedenergyweapons.ap/index.html...
At the same Air Force Research Laboratory in New Mexico, researchers working with Raytheon Co. have developed a weapon called the Active Denial System, which repels adversaries by heating the water molecules in their skin with microwave energy. The pain is so great that people flee immediately.
"It just feels like your skin is on fire," said Rich Garcia, a spokesman for the laboratory who, as a test subject, has felt the Active Denial System's heat. "When you get out of the path of the beam, or shut off the beam, everything goes back to normal. There's no residual pain."
A Humvee-mounted Active Denial weapon is expected to be given to all services by the end of this year for evaluation, with a decision about deployment expected by the end of 2005.Add in an overriding directional radio navigation beacon (VOR) and you've got yourself a mobile small plane assassination unit. You just park near an overcast airport, draw the small plane off course, and zap the cockpit with microwaves. No fuss, no muss.
I wonder if this has ever been tested ...