Thousands of commercial flights transport passengers all over the world every day. And while soaring through the sky at hundreds of miles an hour seems like a dangerous way to get from one place to another, the men and women who work onboard these flights are highly trained to handle any type of emergency.

So it’s safe to say that airline employees know everything that occurs behind the scenes… things the public would have no idea about. Luckily, these pilots and flight attendants decided to spill the beans on 20 fascinating secrets about flying!

1. Anyone who’s flown in an airplane knows about the “stow portable electronic devices” rule, but do they know why? Cell phones can interfere with air traffic control frequencies, which can be an issue during the takeoff and landing. Also, in the event of an emergency, electronic equipment can become projectiles!

2. Automatic upgrades to a higher class don’t happen very frequently. However, according to one flight attendant, they’re pretty much done at the crew’s discretion and can happen for a number of reasons. Passengers might be upgraded if they’re kind, obviously pregnant, good-looking, or even a friend of a crew member.

3. The most annoying beverage for flight attendants to pour is Diet Coke. Because of the extreme amount of carbonation and the plane’s altitude, the liquid takes about three times as long to settle in the cup. This significantly cuts into the attendants’ service time.

4. The first order of business for a flight attendant is his or her professional duties, of course. Still, there’s no rule that prevents them from fraternizing with the passengers—and possibly finding a romantic connection with one of them!

5. Couples who are feeling particularly frisky might try to escape to the bathroom to join the “Mile High Club,” but here’s something a lot of people don’t know: the bathrooms can be unlocked from the outside! It’s an emergency precaution.

6. Just how healthy is the food that airlines serve thousands of miles up in the air? In general, it’s not healthy at all. Don’t expect a nutritious meal when you’re flying; instead, load up on healthy snacks before takeoff.

7. United States Air Marshals are stationed aboard nearly every flight, but it’d be extremely difficult to recognize them. They’re in position to prevent any type of onboard criminal activity or terrorism. (Just don’t expect them to tell you about it.)

8. As you board a plane, the flight attendants will typically line up to smile and greet you. Even though it looks like they’re being nice, they’re actually giving each passenger a visual inspection to see who might potentially be a problem during the flight.

9. There’s a myth that passengers should tuck their heads between their legs during a crash landing for a quicker and painless death. However, this position is actually meant to protect vital organs and increase the chances for survival. Big difference!

10. If every single person on a flight brings with them an extremely heavy suitcase, could will bring the plane down mid-flight? Not at all! The airline industry actually loads the cargo hold with sandbags for weight distribution to ensure a smooth ride.

11. If an emergency situation unfolds during a flight, flight attendants are trained to act as first responders; they can perform CPR or the Heimlich maneuver. There are first-aid kits aboard every plane as well, and in dire situations, the pilot is able to land the plane at the nearest airport.

12. If you’re thirsty mid-flight, never ever sip the water from the bathroom sink. The water that attendants use for coffee and tea may not be the cleanest, either. Just to be safe, wait for an attendant to pass by and ask for the bottled stuff.

13. Due to the quick turnover between some flights, many planes don’t get the thorough cleaning they should before the next batch of passengers board. You should bring some disinfectant wipes along with you just to be safe.

14. The flight attendants and the pilots don’t eat the same food as the passengers. The reasoning behind this is to avoid potential food poisoning; you don’t want the people controlling the plane to have to run to the restroom every few minutes!

15. Indulging in an alcoholic beverage on a plane is perfectly legal. That said, if you overdo it and an attendant finds you acting up, not only will they cut you off, but you can also face criminal charges, as well.

16. If you’ve ever been on an overnight flight, you’ve probably noticed the interior lights are dimmed just before the landing. This is so passengers’ eyes can adjust to the dark in case an emergency occurs and the lights go out.

17. Even if both engines fail, aircrafts are designed to glide approximately one and a half miles for every 1,000 feet of air—and pilots are specially trained to land a gliding aircraft.

18. The drop-down oxygen masks above each seat have about 15 minutes of air built into them. That may not sound like a lot, but 15 minutes is more than enough time for the pilot to reach an altitude where cabin pressure will equalize and the masks are no longer necessary.

19. In case of a crash landing, do you know which area of the plane is the safest to sit in? There are plenty of variables that go into that answer—including seat belts and proximity to the exits—but statistically, the rear third of the plane offers the best chance of surviving a crash.

20. Throughout a flight, you might hear a lot of electronic beeps and chimes coming from the equipment. Although the passengers wouldn’t know it, many of these sounds are actually telling the flight attendants different bits of information throughout the flight.

The next time you take flight, keep in mind these facts. They might just make your journey a little more interesting!

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