When you travel on an airplane, Sitting on a long flight with nothing to do can you think of all sorts of questions. Did you know?, I tell you that there are holes punched at the bottom of the window. Have you not noticed it before?
Ever wonder why there’s a tiny hole at the bottom of airplane windows? The first thing you need to know is that an airplane window is made up of three panes: the outer pane which functions as the “primary structural window;” the middle pane, where the hole is located; and the inner pane, the one closest to the passenger.
Between the outer and middle panes is a small space called the “air gap.” Together, the two panes and the gap constitute the “two-pane air-gap design,” which is prepared to take on the full force of atmospheric pressure. via