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If you've ever been bored at an airport, you've probably spent some time staring out the window

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at the airfield. Occasionally, you might have noticed a plane that looks vastly different than

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the others, like Korean Air's sky blue paint jobs, Spirit Airlines' obnoxious yellow livery,

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or maybe one of all Nippon Airways' Pokemon themed jets. These designs really stand out

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in a sea of plain white planes. But that leads us to an obvious question. Why is white the default

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color for passenger airplanes? Corrosion control is essential when firing a metal tube through

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the atmosphere at over 500 miles per hour on a regular basis, which is the primary purpose of

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a plane's paint. Prior to the 1950s, planes weren't typically painted white. In fact,

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they often weren't painted at all, just regularly polished, because the paints available were heavy,

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expensive, and didn't adhere well to the metal fuselage. But primers and paints gradually improved

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in adherence and durability. Bare metal required polishing roughly three times annually, while

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a new coat of paint is only needed every few years, making polishing around 0.06 to 0.3%

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more expensive. And that's reason enough. But paint can add significant weight to a plane,

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so paint for commercial aircraft is ideally both durable and lightweight. According to Boeing,

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the typical white paint on a large commercial aircraft like a 747 adds up to 555 pounds when

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dry. It's a tiny fraction of the overall weight of the aircraft, but every pound of weight increases

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the fuel burned during takeoff and flight. That's part of why most airlines charge fees for luggage,

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because regardless of whether you pack less or pay up, they're maintaining their profit margin.

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However, there's a common misconception that paints that are lighter in color are also lighter in

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weight, and that's why planes are painted white. While it's true that a higher concentration of

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pigment will result in heavier paint, the total weight depends on the specific pigment being used,

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not necessarily the color. But if white paint isn't any lighter weight-wise, why are so many

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planes white when they clearly don't have to be? White paint has a high albedo, meaning that it

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reflects most of the light that hits it, while darker pigments absorb sunlight. This means that

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dark paint leads to excess heat and more fuel expended on cooling the cabin so you don't bake

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like a potato during your trip. And that extra fuel again costs the airlines more money. Dark

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paint is also likely to accrue sun damage faster, basically the opposite of how it works for people,

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because the dark pigment absorbs more UV radiation, which breaks apart the molecules in the paint.

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Minimizing damage and heat from solar radiation is also why satellites, space shuttles, and the

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international space station are white. We usually think of space as really cold, but since the vacuum,

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there's no atoms floating around to allow heat transfer in the form of conduction or convection,

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which means that a black surface in space can get insanely hot when exposed to solar energy.

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White paint also has other advantages. While military planes are often painted gray to blend

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into the tarmac or a hazy sky, commercial planes need to be as visible as possible on the tarmac.

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Some runways are busy 24-7, even in terrible weather conditions. And while collisions are rare,

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that extra visibility matters. White paint also makes it easier to spot cracks and other kinds

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of damage to the aircraft exterior before packing them with people. Generally a good idea. And that's

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why commercial airplanes are white, because it reduces heat, saves money, and increases safety.

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Now, if only they could increase the leg room. Am I right? Okay. Hey, if you're the type that

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wonders why other things are the color they are, go check out this video next,

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where we explain why so many circuit boards are green.