You've probably heard all the standard tips about air travel: wear comfortable clothing, stay seated when the seatbelt light is on, and don't try to bring drugs on the airplane.

William Cho/Flickr - flic.kr

But a Reddit thread posted on Thursday revealed some of the lesser known things about flying, according to flight attendants.

Austrian Airlines/Flickr - flic.kr

ATTN: also spoke with flight attendant Rachel Cardoza of Southwest and here are the eight things you may not have heard of but should keep in mind the next time you fly.  

1. The tray tables are dirty.

If not dirty, then at the very least, not totally sanitary. "Tray tables are rarely if ever sanitized do not put food directly on them," Reddit user dallenhill wrote.  

"The trays aren't cleaned as often as they should be. Bring sanitizer for your hands," Cardoza told ATTN:. 

2. Seriously, plane cabins are gross.

"All the handles, buttons, rests and over head storage is never wiped down or sanitized after each flight," Cardoza said. She added that the dirtiest part of the plane is a tie between "the over head [storage]" and the "bathroom [door] handles." To avoid the germ ridden area and possibly getting sick, she recommends bringing hand santitizer. 

"Arm rests in airplanes aren't wiped down either," she went on to say. 

3. Don't walk around barefoot or in socks. Don't even wear flip flops.

"Former flight attendant here," wrote Redditor TJeffersonsBlackKid. "Keep your shoes on. Keep. Your. Shoes. On. The floor is so filthy it's ridiculous. And that isn't water you are feeling." Cardoza agrees, and goes even further: "I do not recommend people walking around in socks or barefoot. I also highly advise against walking around in open-toed sandals and flip flops." She explained that the floor of the airplane isn't clean. "They aren't vacuumed in between flights or swept. There is only a quick run-through for trash pick up and that's it," she added. 

4. It's not illegal to have sex in the airplane bathroom.

But it's not encouraged — or recommended — either. "If you knew how dirty they were you would probably think twice," Cardoza said. "I once had a couple in one of the bathrooms 'do the deed' and one of them ended up sticking their hand in someone else's feces." This is also a good time to mention that, according to Cardoza, the bathrooms aren't given a deep cleaning ("just a quick run-through between flights").

5. The plane might be too loud for your pets.

If you're traveling with pets that are boarded in the cargo hold (as is the case if the breed is too large to be considered a "carry-on"), you may want to reconsider. "[Your pets] are treated really well, but people don't understand that [the animals] are exposed to extreme levels of noise that can damage their ear drums," Cardoza explained. "When they are loaded up on the ramp to be loaded onto the plane, they are exposed to the noise pollution airplanes put off, and most humans and workers have ear plugs in that are on ground level. Imagine what the pets are experiencing who have sensitive ears."

6. Flight attendants can accept tips.

If you want to show your appreciation, you can tip or give a small token of appreciation to your flight attendant. "Something that's often forgotten or over looked is that we flight attendants can take tips or gifts. We are in the service business so anything is always appreciated," Cardoza said. "Those customers who take time to notice the flight attendants and their hard work and offer politeness, respect and willingness to adjust, are always treated better."

The average entry-level flight attendant earns about $25,000, annually, so while tipping is at your own discretion a letter or email of praise for a specific crew member or team would go a long way, too. 

7. Want perks? Be nice.

Sometimes there's real perks to showing appreciation. "You have a higher probability to be moved to first class if there's room," Cardoza advised. "One of the girls I fly with has a familiar face fly with her often for work. He always brings her a coffee, magazine, soft drink, or treats every flight, and she always gives him extra perks, extra snacks, first class bump, free wifi — just depends on the day. Little notices go a long way." Of course, you should be polite regardless, and Cardoza's suggestion to be kind is in no way a guarantee of a first class upgrade or any other flight amenities.

8. Flight attendants don't make the rules — and there's a real reason why you can't recline during takeoff.

Flight attendants enforce the rules, not create them. "The FAA [Federal Aviation Administration] makes the flight rules, not us," Cardoza explained. "We have a code we have to go by, even if we don't agree. Don't blame us and get unruly." Reddit user dallenhill points this out, too: "We do not ask you to put your seats in an upright position during takeoffs and landings because we are jerks. It's because we have ninety seconds to evacuate the plane in case of emergency and your reclined seat may impede the person in the row behind you from getting out."

Now, with those eye-opening tips in mind hopefully flying just got a lot more easier for you.