A Boeing 747, a common commercial airplane, holds about 366 passengers. Considering it's summer, the flights are usually pretty much guaranteed to be full depending on your destination. So, with just 366 passengers on your flight alone and millions of people coming and going in any given airport, some etiquette is in order. Here are 15 rules you should know before even stepping foot in the airport.

1. Sickness

If you're too sick to fly, then you're too sick to fly. Imposing your germs on others is a big no-no and also a health risk to yourself. If you're sick but can still fly be prepared.

Have plenty of tissues, medication, and anything else you may need. If you've got to cough, do it into your arm. This keeps it going into the air or onto others. Bring a plastic bag with you to put used tissues so they aren't overflowing on your tray table, what others will be eating off in the future. Have hand sanitizer with you and use it frequently. Oh, and obviously make sure you aren't contagious.

2. Entertainment for those long flights

Keep in mind other passengers when choosing entertainment. For example, if sitting next to a seven-year-old you might want to rethink watching something raunchy and X-rated. Or watching a comedy that has you in stitches of laughter might disturb the sleeping baby and cause an eight-hour screaming infant backdrop.

3. Airplane temperatures

It can be very cold on airplanes, so bring a light jacket with you even if your destination is somewhere scolding hot. Unfortunately, while it can be very cold at times, it can also be very hot. Blasting the airconditioning on yourself is fine, but make sure you aren't freezing everyone else around you.

Keep it pointed at yourself, and leave other people's air conditioning nozzle alone.

4. Reclining seats

While some people might wish for the illegalization of putting your seat back on a flight, it is perfectly allowed. However, there is an etiquette to follow with this as well. Do not put your seat back to max capacity. You'll be practically lying in the person behind you's lap.

If there are entertainment screens in the back of headrests, doing this also makes it impossible for them to view their screen. Not cool. Also, when taking-off and landing, do not wait until you are asked to put your seat upright. You know you've got to do it and flight attendants deserve your respectful following of the rules as well.

5. Tapping screens

We get it. Sometimes those in-flight entertainment screens stuck in the back of the headrests are hard to get to respond. That is no excuse to start jabbing your finger at the screen like a madman. The screen is touch sensitive, not pressure sensitive. If the screen is hard to get to respond, use the pad of your finger to tap, not the tip. Jabbing at the screen repeatedly just ends up giving the person in front a head injury.

6. Knees down

Would you want to go eight hours with someone's knees in your back? No? Then keep your knees down and don't force that onto the person in front of you to go through that either. Those airport seats (especially economy) aren't that thick, and knobbly knees or not, having someone's knee in your back is bad for the spine.

7. Feet in shoes

Keep your socks on if you're wearing them and your feet in your shoes. It doesn't matter how fresh and clean they are or smell. Nobody wants to see them. Plus, if the plane turns or there is turbulence and they go tumbling one way or another that's your problem and you'll have to get yourself out of that. Also, just a word of warning, the floors of planes are very dirty even after they've been cleaned.

You never know if someone stepped in something nasty before getting on the plane. Just saying.

8. Carry-on and personal item

If you can't lift it, you don't bring it. Nobody is your valet and they won't be helping you out. Also, and this is the most important part of this, do not overtake the overhead bins. Don't do it. Don't even consider it. Everyone is allowed one carry-on item up there. If you've got a coat, either fold it up and put it in or on top of your carry-on, or put it under the seat in front of you. Other people have carry-ons that need to go up there. Your personal item has these rules, too. You can have one personal item under the seat in front of you. Don't let it spill into the person next to you, or between the person in front of your legs.

You are responsible for keeping it from rolling all over the place as well. Also, if it doesn't fit under the seat or above in the overhead bin, congratulations you've got an additional checked luggage. If you've made it on the plane without this being spotted, you'll need to give it to a flight attendant and they'll put it below. Usually, they'll do this free of charge, but not always. Check that your items fit with the allowed sizes for your airline and flight. These measurements can usually be found on their website.

9. Personal space

This goes with sitting and watching the clouds outside the window to sleeping. Keep yourself to yourself. Your personal belongings need to be in their allotted space.

That means in your carry-on above, and it's areas (like under it or on top if there is room), under the seat in front of you, or on your seat. Do not ask a fellow passenger to give up their space to fit your stuff. When sleeping, keep your head in your seat. If you're by the window then you can rest it on the side of the plane. This means if you know you have a tendency to tilt over when sleeping, try getting a window seat or one of those neck pillows. Don't end up using your fellow passengers as pillows. Legs to yourself as well. Splaying is fine as long as it's within your seat. You are not a peacock spreading its wings to impress its mate! There is no reason for you to invade other people's space.

If you need more room then you'll have to pay for it in economy plus or something equivalent.

10. Armrests

Middle seat gets armrests. It's as simple as that (I didn't make the rules).

11. Seat-switching

You are morally obligated to offer to switch seats if you're asked, and absolutely have to offer if it is a family especially if it is a family with young kids. Now, obviously if you're also travelling with family or young kids then this is not so, but if you're an adult and you absolutely do not have to sit where you are sitting, then you've got to switch. It's just the polite thing to do.

12. Airplane row shuffle

If someone has to get up during the flight and you're in the way, you're not to make them climb over you.

First of all, that's weird. Nobody wants that and it's uncomfortable to all. Second of all, it's far too easy for falls to happen so it's also a saftey thing. You'll need to get up and step into the aisle to let them through. None of that half-standing either. If the other person does not get up to do this, get up anyway. It'll send the message for them to follow your lead and unless they want to look bad, they'll do it.

13. Scents

This is logic. You're sitting in a metal oval flying through the air. You can't exactly open the window and air it out. Be conscious of your scent. Apply deodorant. Apply perfume or cologne. Wash with soap before your flight. Just make sure you don't smell bad. You might not smell it, but others definitely will so err on the side of caution.

Be careful, however! Drowning yourself in cologne or perfume is not okay either. Nobody wants to be gaging on your scent, no matter how expensive and good it may be. Also, allergies. Some people can have serious medical reactions to strong scents. Take this all into consideration and find a happy balance.

14. Talking

Don't force anyone into a conversation. Some people are talkers. Some people aren't. There is nothing worse than being stuck next to someone who can spend ten hours chatting away seemingly without taking a breath. You don't know if that person is exhausted or how they are feelings. They might need to sleep or might be feeling very emotional and simply don't have the emotional availability to discuss your Travel plans with you.

If you do talk, use your inside voice. No yelling or even loud talking. Other people are trying to sleep and also simply don't care what you have to say. The truth hurts, I know. If you've got a naturally loud voice take the extra effort to keep your voice down.

15. Onboard lavatories

Respect the onboard lavatories. As mentioned at the start of the article. Your flight might be holding 366 people in it or more. If those lavatories aren't respected that flight can turn into something awful pretty fast. When you go to the lavatory, go to the one you are allowed to. This means if you are in economy, you go to the lavatory in economy. You also go to the lavatory nearest to you. Unless it is an emergency, in which case all bets are off and if anyone says anything you just have to inform them that it is an emergency.

Don't use that lightly. When in a lavatory, be respectful of the cleanliness. Don't use all the toilet paper. Don't get water everywhere. Don't dirty up the sink. Be mindful of how much time you are taking. There is more often than not a line, so taking your sweet time is... let's be polite about it and say frowned upon. Only use the lavatory if you need to and for what it is there for. Don't go in and get changed or fix your hair. Other people need to use it after you so treat it kindly.

Too long, didn't read

Overall, you've got to keep in mind that you are not the only one flying that day. Importantly, everyone else has paid for that flight just like you have. You have no right to ruin it for them. If you think you're doing something that might be an action that you would ordinarily turn to someone and ask, "Do you mind if I [insert action here]" when in public, then your best bet is not to do it or ask. You are in public. Do not forget. This is not your house, and if you're about to do something remember others have not consented to it. Be kind and have respect. The rule of thumb here is that consideration goes a long way.