✈️ Air pressure drops as you get higher. But airplanes are designed to maintain air pressure at a safe level inside the cabin.

✈️So the air pressure outside an airplane is much lower than it is inside.

✈️This difference in air pressure puts a lot of physical stress on the airplane window.

✈️Airplane windows consist of three separate panes.

✈️The outer pane deals with this air pressure difference.

✈️The tiny holes in the middle pane, known as the “bleed hole.” Its primary purpose is to balance air pressure.

✈️There’s a small gap between the middle and outer panes.

✈️ The “bleed hole” allows pressure to balance between the passenger cabin and the air gap.

✈️ If something happens to the outer pane, the second pane acts as a fail-safe option.

✈️ The inner pane is “non-structural” but it helps protect the middle and outer panes from damage caused by passengers.

✈️The “bleed hole” also releases moisture from the air gap. This prevents the window from fogging up or frosting over.