If this summer's trip abroad will be your first time on a plane, a few unwritten rules of the airways for those crammed into steerage -- err, coach -- are worth knowing: learning the plane etiquette, which is basically common courtesy at high altitude in a relatively tiny metal tube with seats, will help you avoid unpleasant encounters with fellow passengers whom you can, very accidentally, inconvenience as you all violate each other's personal space for a few hours.
The Elbow and Armrest Dilemma
Just whose armrest is it, anyway? Well, if you're in the middle, more power to you if you want to seize sovereignty of armrest territory: the window and aisle already have one each of their very own, thus, the middle seat gets both the interior armrests. Feel free to enlighten an armrest-stealing seatmate regarding this rule.
Better yet, don't get stuck in the middle -- choose a window or aisle seat when you buy your ticket.
Place Your Bag Over Your Seat
I'm always surprised when the overhead bin above my empty seat row is already full when I arrive, but it turns out that some travelers keep an eye on their bag by storing it one row ahead of where they're sitting. These passengers are afraid that someone will steal their bag, so place it in an area where they believe they'll be able to notice if it's taken. Personally, I've never heard of someone stealing someone else's carry-on bag, and think it would be incredibly noticeable and quickly resolved if someone was to try it.
The problem with this tactic, though, comes when I then have to walk to a different area of the plane to find a free spot, then squeeze my way back to my seat. Then the passenger sat there won't be able to place their bag above them, and the pattern continues. If this happens to you, then you'll need to practice zen and the art of calmly waiting for everyone to get off when the plane lands, rather than shouldering your way down the packed aisle to retrieve your carry-on bag.
Keep Out of the Aisle
When you board the plane, try to put your bag up in the overhead cabin bins and sit down in your seat as quickly as possible. It can be frustrating for everyone except (apparently) the person doing it to watch someone stand in the aisle and rummage endlessly in a bag inside a bin whilst everyone else waits, bags on shoulders.
So, before you board, stash what you want for the flight -- laptop, book, energy bar, lip balm -- inside the small carry on you'll keep at your feet under the seat in front of you. Stow your bigger bag in the overhead bin, sit down, and then rummage to your heart's content.
Don't Recline Your Seat
Nothing gets an air traveler more worked up than the person in front of them reclining their seat.
If at all possible, do not recline your seat. I know that airline seats are shrinking, but you reclining your seat means that the person behind them has to recline their seat, and so on, until everyone's annoyed and leaning slightly backwards.
The advice offered by etiquette experts seems to be to do whatever you politely can or suffer in silence if you're on the receiving end; if this is your first time in the air, know that reclining your seat more than two inches is going to make the person behind you fairly sad for several hours.
If they're polite passengers, they won't be reclining their own seats and thus, thanks to you, your head will practically be under their noses. It's also an invitation to get your seat banged from behind as the squished passenger tries to get into their under-seat carry on despite the seatback in his/her face.
Oh, and you can break the open lid of the laptop on the seatback tray behind you by quickly throwing your seat backwards. As someone who sleeps on their open tray, I can't tell you how many times someone has reclined their chair and whacked me in the head. Fortunately, I haven't had my laptop out at the time. If you must recline, do it slowly enough (after turning around and mentioning that you're about to do it) that the passenger behind you can move spill-able, breakable stuff out of harm's way.
Keep the Window Shade Up
This is a tough one for me.
I'm a nervous flier and if I find myself with a window seat, I like to close the shade, so that I can pretend I'm on a train or in a car instead. However, if I'm traveling alone and don't know anybody else on my row, I keep it open to be polite. Other people may not want to sit in darkness or be unable to see the bright blue sky outside their window, and I like to be respectful of that.
One thing you could do if, like me, you like the shade closed, is to ask your seatmates how they feel about it. If they don't mind whether you close it or not, feel free to keep it shut for the flight. If they do want it open, you could offer to trade seats with them, so they get the window and you don't have to spend the flight trying to avoid looking out of it.
Keep Your Phone on Silent for the Flight
There's nothing more annoying than having to sit and listen to somebody having a phone conversation on a flight -- everyone can hear you and nobody can escape. Whether it's making a phone call with your phone or calling someone from Skype to show that you're online at 35,000 feet, keep your conversation quiet and no longer than a few minutes.
This article has been edited and updated by Lauren Juliff.