The European Union's Security of Aircraft in the Future European Environment (SAFEE) is testing some kind of nebulous facial detection system that will suss out whether your expression is one of a terrorist planning on commandeering the ride or just diarrhea face.
This software will look for nervous face touching, profuse sweating and various other ticks that passengers do all the time. A guy from UCSD built a similar system, but says it only identifies people correctly 70% of the time and only under optimal conditions, which don't exist in airplanes. Sounds foolproof! [Newscientist via Boing Boing]