Jaunted

9. Sleep on you/sleep on the floor
It's a long flight back from Hawaii and your seatmate had two too many Mai Tais. Before you can say "Mauna Loa," he's conked out on your shoulder and speedily producing a lava flow of glistening drool. That is gross; you have permission to push them off. But what do you say when your sitting next to a mom and child, and the sleep child curls up on the floor to sleep? That is pretty bad—already people freak out about breathing airplane air, and yet we've seen children napping, opened-mouthed and sometimes laying on their stomachs, right on the dirty carpets underneath seats.

8. Use the main aisle as a space to do sit-ups, push-ups or change your child's diaper
The aisle is not your gym, nor is it a changing table. No one wants to see your lunging butt centimeters away from them as you attempt calisthenics. Likewise, no one wants to see your baby being changed and smell the reason why. And it's just as important to keep the aisle clear so that flight attendants may do their job.

7. Read Hustler, or other "adult" magazines
We realize that airport bookstores and newspaper kiosks sell adult magazines, but that doesn't mean you should immediately "read" them on the plane; those are for after the flight. It is especially inappropriate and pervy if you are seated next to a stranger.

6. Attempt to join the Mile High Club
Although it seems flirty and adventurous to get in a mood with your partner and try to see things through while in-flight, keep in mind that you're in a public space, and no one likes coming into contact with unknown fluids on surfaces in public spaces. Don't forget that you can also get arrested.

5. Attempt to join the Mile High Club solo
The provided (or purchsed) airline blanket does not mean you have complete privacy and carte blanche to do what you will underneath it. We know the flight might be long, but if others can hold off on smoking for its duration, then yeah. Also, in-flight solo loving is the sure mark of a pervert or someone who desperately wants to end their flight with a trip to jail. Thanks to @BlueNileTravel for reminding of this gross behavior.

4. Eat fried chicken
Don't bring it on a bus, don't bring it on a train, and definitely don't bring it on a plane: smelly, greasy, messy food. Airline meals might suck for the most part, but we're pretty sure that a bucket of chicken isn't the appropriate carry-on option. @stetherado even said that they'd seen someone eat through their greasy take-out meal and then just dump the chicken bones onto the floor. If those aren't cleaned up properly, and say they hang around the plane for a few more flights, then we're looking at suspicious small bones being spotted beneath your seat—yuck.

3. Tend to foot hygiene
There are foot fetishists and then there's everyone else. Feet just aren't the sort of thing that you want spending 8 hours a few inches away from the side of your face, especially if they're not your own feet (doing some yoga there?). Feet can have all sorts of bacteria to rub on your armrest; we're not just talking about passengers removing shoes for the flight. @elizabethdehoff said that she's spotted first class passengers clipping toenails. They may have paid through the nose for their seat, but that doesn't give them the right to gross out everyone else who paid top dollar for first class.

2. Vomit into something that is not the supplied barf bag
Thanks to @eurocheapo, we have a gross image of this in our head: "Saw someone use the plastic wrap from an airline blanket as a barf bag...didn't really work." What happened to the original seatback pocket barf bag? Had they already used it? Being sick in this way on a plane is the worst; but people make it embarrassing by not paying attention to vomit warning signs. Look before you blindly reach into that seatback pocket.

1. Sneeze open-mouthed/neglect to wash hands after using lavatory
This in-flight offense takes the number one spot because it happens most frequently and can affect the most passengers. Letting a big sneeze go without covering your mouth will do more than garner evil looks; your germs could sicken other passengers and coat things in your mucus for the lucky flyers on future flights. And please please please wash your hands after using the lavatory. Already we know that if someone were to put a UV light to an airplane interior, we'd be in big fluorescent trouble, but that is a PSA to think twice about being just as nasty on the plane as you are at home.

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· Travel Health coverage [Jaunted]

[Photos: tripu, andyshaun, emtboy9, The Shifted Librarian, Ye Olde Wig Shoppe]