Even if you’re a frequent flier, there’s probably a lot you don’t know about what goes on behind the scenes. For example, did you know that there’s not much oxygen once those masks drop down? You have less than fifteen minutes before you pass out. In the air, the captain – and the flight attendants – are king. Literally. If you disobey an order from a flight attendant, it’s against the law. These count as federal infractions so you could serve time at the federal level if you get in trouble on a plane. Dehydration is a major issue on flights, but you certainly don’t want to drink the water – the holding tanks in planes are super old and not cleaned regularly. Speaking of cleanliness, don’t even think of using your seat back tray table. It’s used for a variety of unsanitary things, including changing dirty diapers, and guess what? Those seat back trays are not thoroughly cleaned.

Did you know that your pilot may be asleep at the wheel? The phenomenon is more common than you think, with one of the most recent infractions occurring on a British airline. If you’re intrigued – or uneasy – keep reading for 15 shocking confessions from flight attendants.

15. You don’t have a whole lot of oxygen

We all take oxygen for granted when we’re on the ground, but when you board a plane, you don’t realize how little oxygen there is. In fact, once the oxygen masks drop down, there is only about 15 minutes before passing out. So, don’t take the oxygen for granted, and don’t dilly dally in case those masks do come down during your flight. But do not get too alarmed — there is usually enough time for the pilot to take the plane down to a lower altitude in order for you to breathe good old fashioned oxygen.

14. The captain is king

Once those airplane doors shut, the captain’s word is law — quite literally. But before the doors close, if a particularly rowdy passenger is wreaking havoc in the jetway, he can refuse to let them on and leave without them. Once those doors close, that’s when things get serious. A captain can write fines, take the will of a dying passenger — and he can even arrest people. Most passengers are unaware of the extent of a captain’s authority on a plane. So think twice before disobeying the orders of a captain. The plane is his or her kingdom, and you’re a mere subject.

13. The water is undrinkable

Do not drink the water on planes. I repeat, do not drink the water on planes. This includes the water used for coffee, tea and so forth. Why? Because more often than not, the holding tanks in decades old planes are rarely cleaned. Some have allegedly grown greenish grime on the walls. Another reason to not drink the water on planes? The lavatory and potable water are sometimes serviced by the same employee. So, unless it comes from a bottle, just don’t do it. Bring two (or three, for long flights) water bottle, and your germ free digestive system will thank you later.

12. Your pilot may be sleeping at the wheel

Most fliers don’t want to think about their pilots doing anything but paying attention to the controls with razor sharp focus during their flights. But the truth is, pilots falling asleep at the wheel is more common than you would think, which is a terrifying notion. Allegedly, at some point, half of pilots sleep while flying, and a third of the time they can wake up to find their partner sleeping. In fact, back in 2013 it was reported that a passenger jet, an Airbus A330, making its way to the UK was on autopilot when both pilots fell asleep at the controls.

11. The pullout tray tables are covered in fecal matter

You know the pullout tray tables where most of us take our meals during the flight? Most of us have accepted that they’re pretty gross — but we don’t realize just how gross they are. Many dirty diapers have touched those innocent looking surfaces. Passengers even cut their nails on the trays. This wouldn’t be so disturbing if it weren’t for the fact that those trays are not thoroughly cleaned or sanitized to the level they should be. If you must use the setback tray, clean it thoroughly — and I mean thoroughly — before using it, especially if you’re going to eat on it.

10. Wearing your seat belt is more important than you think

Turbulence is a scary thing. A very, very scary thing. But in truth, no one really dies directly from turbulence. The official figures are 3 since 1980, so those are pretty long odds. But two of those three passengers were not wearing their seat belts. It may seem silly when the flight is going smoothly, with perhaps a few slight bumps, but you should really just keep your seatbelt on when you’re ordered to. Most people who suffer injuries are flight attendants, who may be busy tending to passengers and not wearing their seat belts. So, just click them on and avoid scary injuries from sudden turbulence.

9. There may be human remains on your flight

This is pretty common, but many passengers are unaware that human remains may be traveling on the plane with them. In fact, the majority of domestic flights allegedly have human remains — or even organs — on board. If you see a long box that says “head” on one side…well, you know what’s inside. Passengers can even take crematory remains on board the flight as carry on or checked baggage. It may seem morbid, but it’s just a fact of traveling that human remains often need to be transported to different destinations. This is yet another fact that flight attendants are privy to.

8. It’s against the law to disobey flight attendants

If the captain is king, then so are the flight attendants. Why? Disobeying them is actually against the law. In fact, it’s a federal crime to interfere or physically assault ( or even threaten to assault) a flight attendant. That could be a felony conviction right off the bat. Unsurprisingly, if you use any type of weapon, you will also be punished strictly, and possibly face jail time. Now, this is totally understandable. But interfering with the crew members job could be disobeying or refusing to comply with orders, which would be punishable by arrest. The official term is flight crew interference, and penalties include up to 20 years imprisonment and fines up to $250000.

7. You don’t really need to turn off your electronics

At this point, most of us are aware that the whole turning your electronics off is a bit of nonsense. But it is fear inducing to think that any type of plane malfunction could be caused by our iPads or cell phones — and that is often the implication when we’re ordered to turn off our devices. But it turns out that’s a bit of a myth. If anything, electronic devices are just nuisances to the pilots. As they descend to the final destination, it’s irritating to hear a bunch of cellphones trying to get a signal. Annoying? Yes. Dangerous? No.

6. The blankets and pillows aren’t cleaned

Flight attendants know that the blankets and pillows they provide for free aren’t exactly clean. In fact, after use they allegedly just get refolded and placed back in the bins. The fresh ones likely come from the originating flight in an provisioning city. It’s probably a good rule of thumb to assume that most of the amenities provided for free aren’t the most sanitary — so just plan accordingly. It’s better to just use your own blanket or pillow — and if you do use the airlines, perhaps use it as a cushion for your lower back instead — it’s a good way of making yourself comfortable instead of sick.

5. Interior Lights

You may think that the interior lights are dimmed for your inflight comfort. Part of that may be true, but the biggest reason is so that your eyes have time to adjust to the darkness in case passengers need to evacuate the plane. In fact, the interior lights are dimmed to match the exterior environment. So if you’re flying throughout the night, expect the lights to be dimmed. Same goes for dusk or dawn. The lights dimmed even makes those EXIT signs easier to read. So, the next time you’re on a long plane ride and they dim the lights — you’ll know what they’re really for.

4. Lightning often strikes planes

Here’s a scary fact — lightning strikes planes on a semi regular basis. In fact, a plane that was landing at Los Angeles’ LAX airport was struck by lightning — and none of the passengers noticed. On average, lighting strikes every airliner in the air once a year. The higher the altitude, the more likely it is that an airplane will be struck. They also seem to occur more often between March to July. This may seem a little —ok, a lot terrifying— but consider how often they happen and how little passengers seem to notice indicates that this eerie fact is just a quirk of flying.

3. Lavatories can be unlocked… from the outside

Ah, the lavatory. The one place on the plane where it seems like you have some semblance of privacy. But guess what? That’s not the case at all. There is often a mechanism concealed that just needs to be lifted from outside — and voila, the door can open. Now, this can be incredibly helpful for flight attendants. If there is a life threatening situation, they can get into the lavatory easily. But it can be incredibly annoying for those of us who enjoy the brief moments of privacy on a packed plane. Just be aware of this the next time you use the lavatory — privacy is an illusion.

2. Pets aren’t treated well

It’s probably not a great idea to travel with your pet if it can be at all avoided. In general, airlines are not purposefully being callous to animals — they’re doing the best they can given the circumstances. But there is one thing they cannot control — the noise. Ever notice how employees have headphones on as they stand out on the ramp? Well, pets don’t have such headphones. There is also the matter of extreme temperatures and poor ventilation. Two million animals are transported by air every year, so that’s a whole lot of pets. Perhaps leave Spot home during your next trip.

1. Don’t wear the headphones

You would think that the headphones are relatively sanitary, given they they’re typically wrapped in a seemingly secure package. But that may not be the case. The headphones that were in some other passenger’s grubby ears are supposedly cleaned, then merely packaged up again — they’re essentially used headphones. Who knows how much ear wax or bacteria is laden upon those headphones. Just like water, blankets, and pillows, it’s best to just bring your own and not risk using the grubby ones handed out inside those innocent looking packages.