system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do human bodies keep from losing air and crumbling on an airplane unlike a half empty water bottle on an airplane?
gpt
Human bodies aren't balloons. We're mostly liquid on the inside, with some solid. The areas that are gas-filled have systems to equalize pressure with our surroundings. Our lungs should be obvious, but then those little tubes in our ears (the name escapes me) require movement in order to maintain pressure. This is why your ears can hurt when swimming deep underwater or flying in a plane.

The normal solution to this is chewing on gum, as the movement of the jaw helps speed up the pressure equalizing process.