Why are planes white?

White reflects most solar radiation, so a fuselage parked in the sun at a tropical airport heats up far less than a dark one. That reduces the load on ground air conditioning and, above all, protects adhesives, sealants and composite materials in the fuselage, whose strength drops under sustained high temperatures. That's why some manufacturers require radomes and certain composite parts to be painted white or a very light shade. White paint also degrades more slowly under ultraviolet radiation, so the livery keeps its appearance for more years between repaints.

Painting a wide-body aircraft adds several hundred kilograms: a Boeing 747 carries around 250 kg (550 lb) of paint, and every extra coat of color translates into more fuel burn over the aircraft's entire life. White covers well with few coats, while many bold colors need primers and extra layers. On top of that, oil or hydraulic leaks, cracks, corrosion and impact damage are easier to spot with the naked eye on a light surface, something mechanics rely on during every daily inspection. When an aircraft changes operator, a white fuselage only needs new decals and logos, which lowers the cost of the handover and explains why leasing companies prefer neutral liveries.

Not every airline follows the rule: Air New Zealand has flown black aircraft, and S7 Airlines and easyJet use bold green and orange as their brand identity. They accept the extra weight and maintenance cost because the brand recognition pays off.