The first thing you notice when your plane suddenly begins to drop is that you're becoming weightless. For those who like roller coasters, the sensation may not be too bad. Quickly, however, zero-G can become negative-G, meaning anything not fastened or seat-belted down will slam into the ceiling. Food trays get tossed, cutlery gets flung, carry-ons fly up as tray tables bang down. After a few seconds the plane stabilizes, and anything--or anyone--stuck to the ceiling crashes to the floor. Another case of midair turbulence is quickly over.
Last week United Airlines Flight 826 from Tokyo experienced this special brand of...