Airplane windows aren’t just single pieces of glass. They’re made of three panes: the outer, middle, and inner. Each has a job to keep you safe and comfy:
Outer Pane: The toughest one, built to handle the big air pressure difference between the cabin and outside air.
Middle Pane: Acts as a backup if the outer pane has a problem. The bleed hole is here and helps control pressure.
Inner Pane: Mainly for protection, so you don’t accidentally damage the other panes.
Together, these panes keep the cabin pressurized and give you a clear view.
Airplane cabins are pressurized so you can breathe easy as the plane climbs to high altitudes where air is thin. As the plane goes up, the air pressure outside drops a lot compared to inside. This creates a big pressure difference that could stress the windows.