On all large commercial airliners passengers have to sit through a life jacket demonstration.
Does anyone know whether anyone’s life has ever been saved by such a life jacket in a “large” airliner? All the crashes I’ve heard about just crash and that’s it!
It keeps your body (or parts thereof) floating, so they are easier to find. 
Actually, I heard on one of those Discovery channel shows that goes behind the scenes of NTSB investigations that in the 1 in whatever millions chance that you ever get into a plane crash, you are more likely to survive it than check out (which seems hard to believe).
Also, for those annoying over/undershoot the runway accidents, life jackets might come in handy.
To make a short story long (and to get back to the OP), I seem to recall video of the Potomoc (sp?) river crash and people swimming with jackets on.
I posted some stats on crashes here:
http://boards.straightdope.com/sdmb/showthread.php?threadid=26248
It includes all civil aircraft, including air carriers (which itself includes air taxis).
Aircraft life preservers make a great gift.
And not only are they festive, but yellow is trendy now!
Could it just be for well, how do I put it-to make it LOOK safer?
There was also that large A 300 or something like that South American Airways airliner that crashed just off of the coast while being video-taped. I recall that some people believe that people deploying the jackets inside the craft before it hit the water caused them to be trapped inside, but it sounds like bullshit to me. IIRC, a large number of the survivors were found floating with life jackets on, suffering from shock, barely conscious, and hardly able to swim. It would seem that it saved these people’s lives.
Yeah, the plane was being hijacked and the hijacker didn’t believe the pilot when the pilot told him they didn’t have enough fuel to get to the hijacker’s destination.
People inflating the LPUs inside of the aircraft is bullshit? Never underestimate the stupidity of the average person! Okay, that’s a little harsh. Let’s just say that untrained people do strange things in a panic situation. I would not be at all surprised if, in a group of a couple hundred people, a few of them were a little premature in inflating the LPU.
A little off-topic, but I thought I’d throw in some trivia. Naval Aviators have devices on their LPUs (I think the devices are called FLU-8s) that inflate the LPU automatically when the aviator hits the water. These devices are not on Naval helicopter pilots’ LPUs, as the vest must not inflate until after the crew are out of the airframe. (Heli pilots in the Navy and Marines often carry a small bottle of compressed air in their survival vest in case of a water landing.)
So would this be ‘Premateur Hijack-Flotation’? 