Why most aeroplanes are painted white?

1. White color radiates heat. Commercial airplane cruises at a height of 35,000 feet and the sun rays are most effective, so to keep the cabines cool they are painted white.
2. Paint weight also plays a vital role, on painting it gains an additional weight of 550 kilograms to 1,100 kilograms keeping in mind the size of the aircraft. Calling for a design or a pattern of different colors will end up adding a third layer of paint to it, which will increase the weight of the plane by almost 550 kilograms, which will burn out extra fuel. 
3. Cracks, Corrosion, or Oil spills are easily visible on white color. So to ensure safety for the passengers, with regular maintenance they are often painted white.
4. The colors of airplanes are of a special type. For the supersonic passenger jet "Concord" a new type of paint was developed. To get these paint easily available during the repainting process, they are painted with a common paint scheme of white. Moreover, the cost of the white color is quite low.
5. The dark color when exposed to high temperature and solar radiation,it starts to fade and in time costs the airline company around 50,000 USD to 200,000 USD for its repainting process.
6. Birds like Vulture, Eagle, etc fly at a height of around 20,000 to 39,000 feet, where most commercial jets cruise. According to research, it is found that white is the most visible color in the sky. So to avoid bird strikes, they are painted with white color.
7. Various airline companies buy used planes, mostly for cargo, and as the repainting cost is much higher, they try finding out a similar paint scheme to avoid repainting the full jet. It also gets easier for the companies to sell out their used planes with the similar coloring of 'white'
8. During a crash, it gets easier for the search and rescue team to track the plane remains.