Why Are Airplane Windows Round? Plus, 6 Other Common Airplane Mysteries Explained

Travelers can always count on experiencing the same familiar features during a flight, regardless of the airline and class status they choose. There’s the pre-flight safety demonstration, the mid-flight peanuts-and-cocktail combo, and the routine announcement to turn your phone onto airplane mode. But when you’re strapped to seat at 35,000 feet for a few hours, you begin to notice -- and subsequently question -- every detail, like the tiny hole in the middle of your airplane window and the fact that your window is round, not square. And, while we’re at it -- why doesn’t your window line up with your seat? You paid for a window seat, after all. Below, we unravel seven unusual airplane mysteries.

Why do the lights dim during takeoff and landing?

While it certainly sets the mood (and helps you slip into some shut-eye), that’s not the real reason the lights are lowered during takeoff and landing. Dimming the cabin lights, which is done as a safety precaution, allows your eyes to acclimate to darkness, so that you are not abruptly blinded in the event of a power outage or emergency evacuation. According to The Telegraph, it can take your eyes up to 10 minutes to adjust to a dark setting, so softening the lights helps you adapt faster. Plus, the floor lights and safety signs become more visible in low-light conditions -- not to mention, it is easier to calibrate to the darkness outside when landing during the nighttime. 

Why are you required to raise the window shades during takeoff and landing?

Similar to dimming the cabin lights, raising the window shades during takeoff and landing is done a precautionary measure. (And here you thought it was so you can enjoy the view.) Passengers are asked to comply with this procedure so that the cabin crew can check the conditions outside (in case of a fire or another hazard) and assess which side of the aircraft is safest to use. During the daytime, open window shades also fill the cabin with light, offering passengers, cabin crew members, and a potential rescue team a clearer look inside the aircraft. It also ensures that passengers’ eyes are acclimated to the daylight if they need to evacuate quickly. A sudden change in light can be disorienting.

Why do you have to put your seat in an upright position during landing and takeoff?

Although rare, most airplane accidents occur during takeoff and landing. So, the Federal Aviation Administration (FAA) implemented the upright seat rule to make it quick and easy to evacuate in an emergency. Besides ensuring a speedy exit -- reclined seats won’t slow you down -- this procedure also minimizes your chance of hitting your head during a bumpy ride.

Why is there a small hole in every plane window?

Anyone who has ever had a window seat on a plane has probably noticed a tiny hole in the middle of the pane. Turns out, it has a name -- breather hole -- and it serves more than an aesthetic purpose. In fact, the small hole plays a big part in ensuring the safety of passengers, as it controls the amount of pressure that passes between the interior and exterior windows. The air pressure is greater inside the cabin, allowing you to breathe normally. Moisture is also released from the hole, ridding the window of any fog so you can still score that Instagram-worthy shot of the airplane wing hovering over a stunning landscape.

Speaking of windows, why are they round?

Ever wonder why airplane windows are round? Well, there’s a solid explanation for it. Earlier airplane models that featured square windows fell apart while in the air, due to the sharp angles that were weakened by air pressure. Circular windows, however, are able to distribute the pressure more evenly, and thus, reduces the likelihood of it breaking midair. The design flaw was fixed -- and airplanes from that moment on only featured curved edges.

Why don’t airplane windows line up with the seats?

There’s nothing worse than purchasing a window seat and boarding your flight only to discover that your seat is aligned with the blank wall, instead. Apparently airlines choose the final layout of the cabin, controlling not only how many rows should exist, but also where they should be positioned. Not surprisingly, it is the airline’s goal to cram as many passengers into the flight as possible. Therefore, this reduces your legroom and steals your prime window spot.

Why are there ashtrays in airplane bathrooms?

It has been more than two decades since smoking was banned on flights, yet ashtrays still reside inside every plane lavatory. So, what’s this mixed-message all about? Despite the illuminated “no smoking” signs and captain’s warning announcements, the Federal Aviation Administration (FAA) requires that aircrafts come equipped with ashtrays. That’s because some people still break the law and light up. To prevent those folks from tossing a cigarette into the trash and potentially causing a fire, airlines take the better-safe-than-sorry route.

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