Fear of flying | Welcome aboard | Economist.com:
The flight attendants are now pointing out the emergency exits. This is the part of the announcement that you might want to pay attention to. So stop your sudoku for a minute and listen: knowing in advance where the exits are makes a dramatic difference to your chances of survival if we have to evacuate the aircraft. Also, please keep your seat belt fastened when seated, even if the seat-belt light is not illuminated. This is to protect you from the risk of clear-air turbulence, a rare but extremely nasty form of disturbance that can cause severe injury. Imagine the heavy food trolleys jumping into the air and bashing into the overhead lockers, and you will have some idea of how nasty it can be. We don't want to scare you. Still, keep that seat belt fastened all the same.
Your life-jacket can be found under your seat, but please do not remove it now. In fact, do not bother to look for it at all. In the event of a landing on water, an unprecedented miracle will have occurred, because in the history of aviation the number of wide-bodied aircraft that have made successful landings on water is zero. This aircraft is equipped with inflatable slides that detach to form life rafts, not that it makes any difference. Please remove high-heeled shoes before using the slides. We might as well add that space helmets and anti-gravity belts should also be removed, since even to mention the use of the slides as rafts is to enter the realm of science fiction.