I'm sure the woman flying Pakistan International Airlines last week heard her own version of "gotcha" when she got off the plane in Lahore - because she was supposed to be in Paris. For reasons that remain unclear, she slept through the landing, slept through the layover and apparently slept through at least part of the return trip. 18 hours on a plane and why a flight attendant didn't wake her is anybody's guess.
Most air travel "gotchas" are not so extreme, but they are annoying and sometimes expensive. Here's how to avoid the worst of them.