Airplanes protect people from decreased air pressure when flying at a high elevation by using something called cabin pressurization. Cabin pressurization is when a cabin in a plane is filled with pressurized air. This air allows us to breathe when we are at a high elevation. The air is pressurized through the engines, and the air stays in the cabin because it has nowhere to escape. An example would be a aluminum can of soda. All the air stays inside without escaping, so when you open a can the soda is fresh. In the picture to the right, it shows how the engines pressurize the cabins, allowing you to breathe instead of suffocating in the airplane.
