Airplane windows have real holes in them
If you travel by plane frequently, you may have noticed that airplane windows have little holes in them. Don’t worry, those holes are just where they should be.
Those holes are meant to keep the plane’s air pressure in check. Because air pressure varies as you move further away from the earth’s surface, your ears explode at high altitudes. The window holes help to regulate some of the air pressure difference, so the outside window doesn’t have to perform all of the work. Additionally, they keep the windows from fogging up.