25 Things You Probably Didn't Know About Airplanes And Air Travel

But how much does the average person really know about an airliner? Well, unless you're a mechanic, pilot or an incredibly frequent flyer, your knowledge of a jet and airline travel is probably limited.

Here are a few secrets about airplanes and air travel.

Yeah, it happens. Odds are, though, you might not even realize it. Airplanes are built to withstand lightning strikes. The lightning runs across the skin of the plane and causes very little damage.

For good reason, you can lock the bathroom door on the inside - and the flight attendants can unlock it from the outside. There is a switch on the outside of the door that can be unlocked, allowing access in case a passenger is sick or incapacitated, smoking, or two passengers are, um, otherwise engaged.

Virtually every airline has this precaution in place, for obvious reasons. The pilot and co-pilot are required to eat separate and different meals just in case one meal is bad. It rarely happens, but think of it as the royal family traveling separately in case of an accident so the line continues. Precautionary.

You might have known there are lights on the outside of every plane, but did you know that two, in particular, are critically important? On each plane, there is a red light on the left wing and a green light on the right. This enables other pilots flying in the dark to distinguish which way oncoming planes are flying.

For every one hour of flight, your body loses eight ounces of water. Welcome to the wonderful world of in-flight dehydration. Be sure to get plenty of fluids into your body. But not alcohol, which can intensify the dehydration.

You would think the last thing you want at 30,000 feet is a hole in the plane. But if you look closely at every window, there is a tiny, tiny hole that actually serves to regulate pressure in the aircraft. And, God forbid, if anything ever happened to the outside of the plane, the hole should prevent the inner pane of the window from breaking.

Stop watching movies that involve airlines losing engines and suddenly dropping from the sky. In actuality, aircraft can fly with one engine. And if that last one fails, even a 747 can glide - in fact, they can glide two miles for every 1,000 feet of altitude. Additionally, if an aircraft loses its final engine while flying at 25,000 feet, a pilot still has about 50 miles to work with to set the plane down.

If ever there was a need for the oxygen masks to drop, know that there's only about 15 minutes of oxygen per person. But that's OK. The oxygen masks are there to keep passengers conscious in the event of cabin depressurization. That's enough time for the pilot to descend and bring the aircraft to an altitude where passengers can breathe on their own.

Although airlines have this down to a science in terms of how much fuel you need in the tank to get from Destination A to Destination B, the Federal Aviation Administration demand that planes carry enough backup fuel to land at an alternate, nearby airport.

Sure it looks like a toilet. Has a seat like a toilet. Has an inordinate amount of blue water, but, whatever. But it's not a traditional toilet. It's a vacuum. Watch the next time you flush to see the silver flap open. Air pressure then sucks what's in the bowl to a tank in the holding compartment.