White has become the standard colour for airplanes' exteriors. While stylish, it's also a calculated decision by many airlines. White essentially reflects sunlight instead of absorbing it, like other colours do. This is great for keeping the plane's interior temperature down. It's the same as getting into a white car on a sunny day—its inside is probably cooler than a black car's would be. And since constant exposure to sunlight often causes many colours to fade anyways thanks to oxidation, white becomes a practical choice. White is easy to spot, whether in the air, on the ground, or in the case of a crash, in the sea. And it's easy to see cracks or chips in the paint when that paint is white. This detection is important because dirt and moisture can quickly collect in these chips, becoming sites of corrosion that could eat away at the aircraft's body. This is one reason, in fact, that planes are usually painted at all instead of being left as polished metal: painted metal more readily resists corrosion than unpainted metal. You'll often see plastic, fiberglass, or carbon fiber painted white on planes, too. This is because these parts of the plane are easily susceptible to sun damage, which the white paint helps prevent. So why aren't all planes pure white? Advertising. After a white base, airlines will often paint their brand name on the side and their colours on the tail of the plane.