Airplane Security Collar
Above is the schematic for an invention by Italian Paolo Valletta that is um, well, it's like a shock collar for dogs, except it injects your neck with a tranquilizer if you start acting up on a plane. Using this device, the flight attendants would be able to knock out any passenger on the plane, or all if necessary. Which, at least for me, is entirely unnecessary. After my typical pre-flight liter of bourbon and handful of sleeping pills I'm usually peaceful. This thing would probably kill me.
Airplane Security Collar [livescience]