Most frequent flyers have had the experience. You squeeze into a tight seat for the long flight. You've brought along your electronic gizmo to do some work.

Then it happens! A 400-pound guy (or gal) stashes his carry-on just above you. You pray he won't be your seatmate. Your prayer is not answered. You get up and he attempts to slide past you to the window seat, heavy flab smooshing your face.

He plops down and instantly overflows into your space. You're squashed in and the arm rest is now covered with his bulk. In that unhappy situation, must you grit your teeth and suffer through the flight? What are your choices? 1. Be understanding. His weight may be caused by a glandular condition, and he's already sensitive enough without you reminding him how it imposes on you. Smile and be determined to endure the discomfort or flee.

2. Without loudly griping at your seatmate, go to the flight attendant, complain quietly that you're very uncomfortable, and ask to be moved to another seat. If refused because it's a full flight in coach, ask that you or the overweight guy be moved to a larger first-class seat.

3. If refused, wait until you're in flight and seat belt sign goes off. Get up frequently and walk the aisle. Go to the back, and if there are empty seats, including those the flight attendants use, sit there for as often and as long as permitted.