Stoping Hijacking..??
Just a thought---------alcohol induced
Pilots in cockpit flying along happily behind locked doors
Air Sherrif in cabin enjoying the flight.
Hijackers or nutters taking over the plane.
Air Sheriff notifies the cockpit with electrical device(or maybe attendant being threatened at cabin door).
Pilots and sherrif slip on different ozygen masks than those those that fall out the overheads.
Hit the magical red button----poof----out comes a sleeping gas ,and everyone passes out.
Air sherrif sorts out the bad guys,then when everyone comes to,the flight continues as normal.