Whose Armrest Is It Anyway?

The fact is, those armrests are so narrow they're barely enough for one person. In a row with three seats across, the passenger in the middle seat has it tough enough, so let that person have both and just keep one for yourself.

If it's what they call a 2x2 configuration, there's more at stake. Which of you gets the shared armrest? If your seatmate seems intent on using that space, take a minute to assess your priorities: Do you really need it, or are you fighting on principle?

For short-haul flight, I say let it go. On a longer journey, I find that a couple of well-timed nudges early in the flight usually make your seatmate willing to share. Should you find yourself in a battle of the elbows, again, take a minute to assess whether this is a war worth fighting.

If the answer is yes, the best option is directly saying, "Do you mind if I get some space here?"

Don't check your common sense at the gate. Learn the golden rules of airline etiquette from the experts

Yes. Apologies to the person in the aisle seat, there's just no way around this one.

Still...I tell travelers to please use common sense. If you're a frequent restroom user, why would you choose a window seat? Overcaffeinating or hitting the airport bar before the flight are also surefire ways to require multiple bathroom breaks, so my suggestion is to pay attention to how much liquid you're ingesting and ward off the problem before it happens.

Learn about dining etiquette abroad

No. Airline seats are made to recline. In economy seats, legroom is so limited that we have to do what we can to survive the flight.

There are some caveats: Airlines have a legitimate safety reason for keeping seats in the upright position at certain times, and mealtime is no exception. A good rule of thumb is to avoid reclining your seat until after meal or beverage service.

Before pushing your seat back, though, be aware of your surroundings. If the person behind you is 6-foot-3-inches tall, take one for the team.

Now what about the person in front of you who insists on reclining at an inappropriate time? I always suggest quietly asking the flight attendant to step in, or you'll risk starting a war.

Or try this little trick: There's a pocket-size gadget called the Knee Defender that you simply stick onto your tray table. It prevents the seat in front of you from reclining (you didn't hear it from me).

If you've got long legs, you might find that it's worth paying for economy plus seats. They have a bit more legroom. Delta, United (and soon, Continental), JetBlue and Virgin America all offer this option on certain flights. To find out which routes, check out the website seatguru.com, which shows the seat configurations of all airlines based on the type of airplane. Even better, it analyzes good and bad seats. According to their experts, a good rule of thumb is premium seating is only worth it if the cost is no more than 15 percent of a standard economy ticket.

What's the flight attendant's role on a plane?

This is another situation when the flight attendant can be your best friend. If there are empty seats, he or she may be able to relocate you or provide a last-minute upgrade.

Interestingly, most airlines' "contracts of carriage" allow them to refuse passage to people based on certain criteria.

For example, American Airlines clearly states in its contract of carriage that it can remove a passenger with an offensive odor not caused by a disability or illness; Delta Air Lines states that anyone who is barefoot, appears to be intoxicated or has a malodorous condition can be refused boarding.

If the problem persists even after you've spoken up, you can always report the situation to the airline after you land. Direct your complaint to your carrier's customer service department; you'll need the date of your trip and your flight number handy. Who knows? They might give you flight credits or bonus mileage points.

Travel guru Peter Greenberg is the travel editor of CBS News and publisher of PeterGreenberg.com.