Reverting to the subject of Air Marshalls, back in the 80s Iran Air had them.
The Captain announced that we were flying at 36,000 ft, as we looked at two guys cradling their AK47s! One itchy finger and we would ALL have been flying at 36,000 feet, but not inside the aircraft!
On another occasion, we were told that RAF Marholm used to train Pilots and Navigators in aircraft equipped with ground following radar. The Flight Plan was recorded onto a cassette tape, which was then played back in the cockpit, to the control system. One of the later flights was for the whole squadron to fly, in a time interval line astern pattern, a LOW level figure of eight route to Scotland, crossing somewhere in Yorkshire, at night. Apparently everyone came back lighter and more moist than when they took off!
Howard