Why airplanes are white in color?
One of the most important reason is that at high altitudes the climatic conditions are erratic and it may oxidize the paint on it.
So if you paint a red or orange in due course it will start fading and it is a recurring expense for the airlines. This is why most of the airlines paint them white as it doesn't fade that easily.
Another reason is that the white paint reflects the sunlight to a great extent and so it can keep the airplane cool inside when compared to other colors. It also reduces their expense in the cooling system and cooling the engine.