MIT Aeronautics and Astronautics professor R. John Hansman told Business Insider that it’s similar to “putting sunblock on.” White paint reflects sunlight and solar radiation which keeps the cabin temperature cool and gives some protection to the vessel from the sun. This helps to keep the cooling costs of the plane lower. White paint is also technically lighter in weight because it is less pigmented which reduces fuel consumption and emissions. It is also cheaper to purchase and does not tarnish as quickly as brighter colors or polished metal.
According to Simple Flying, using white paint also helps keeps passengers safe. A light-colored vessel makes signs of damage more apparent. It helps engineers find oil spills or leaks, cracks, and anything else that might be wrong with the aircraft. Also, white stands out against a blue or dark sky helping birds spot an oncoming plane and avoid a collision.
So aside from Air New Zealand’s marketing play using black-colored planes, you’re unlikely to see many other airlines slashing on multi-colored paint anytime soon. 