If you've ever been bored at an airport, you've probably spent some time staring out the window
at the airfield. Occasionally, you might have noticed a plane that looks vastly different than
the others, like Korean Air's sky blue paint jobs, Spirit Airlines' obnoxious yellow livery,
or maybe one of all Nippon Airways' Pokemon themed jets. These designs really stand out
in a sea of plain white planes. But that leads us to an obvious question. Why is white the default
color for passenger airplanes? Corrosion control is essential when firing a metal tube through
the atmosphere at over 500 miles per hour on a regular basis, which is the primary purpose of
a plane's paint. Prior to the 1950s, planes weren't typically painted white. In fact,
they often weren't painted at all, just regularly polished, because the paints available were heavy,
expensive, and didn't adhere well to the metal fuselage. But primers and paints gradually improved
in adherence and durability. Bare metal required polishing roughly three times annually, while
a new coat of paint is only needed every few years, making polishing around 0.06 to 0.3%
more expensive. And that's reason enough. But paint can add significant weight to a plane,
so paint for commercial aircraft is ideally both durable and lightweight. According to Boeing,
the typical white paint on a large commercial aircraft like a 747 adds up to 555 pounds when
dry. It's a tiny fraction of the overall weight of the aircraft, but every pound of weight increases
the fuel burned during takeoff and flight. That's part of why most airlines charge fees for luggage,
because regardless of whether you pack less or pay up, they're maintaining their profit margin.
However, there's a common misconception that paints that are lighter in color are also lighter in
weight, and that's why planes are painted white. While it's true that a higher concentration of
pigment will result in heavier paint, the total weight depends on the specific pigment being used,
not necessarily the color. But if white paint isn't any lighter weight-wise, why are so many
planes white when they clearly don't have to be? White paint has a high albedo, meaning that it
reflects most of the light that hits it, while darker pigments absorb sunlight. This means that
dark paint leads to excess heat and more fuel expended on cooling the cabin so you don't bake
like a potato during your trip. And that extra fuel again costs the airlines more money. Dark
paint is also likely to accrue sun damage faster, basically the opposite of how it works for people,
because the dark pigment absorbs more UV radiation, which breaks apart the molecules in the paint.
Minimizing damage and heat from solar radiation is also why satellites, space shuttles, and the
international space station are white. We usually think of space as really cold, but since the vacuum,
there's no atoms floating around to allow heat transfer in the form of conduction or convection,
which means that a black surface in space can get insanely hot when exposed to solar energy.
White paint also has other advantages. While military planes are often painted gray to blend
into the tarmac or a hazy sky, commercial planes need to be as visible as possible on the tarmac.
Some runways are busy 24-7, even in terrible weather conditions. And while collisions are rare,
that extra visibility matters. White paint also makes it easier to spot cracks and other kinds
of damage to the aircraft exterior before packing them with people. Generally a good idea. And that's
why commercial airplanes are white, because it reduces heat, saves money, and increases safety.
Now, if only they could increase the leg room. Am I right? Okay. Hey, if you're the type that
wonders why other things are the color they are, go check out this video next,
where we explain why so many circuit boards are green.