A parachute fills with air and breaks the fall of someone falling from an airplane.
If your airplane is in trouble, and you need to jump, your best friend is a parachute. That's the device people jumping from airplanes use to slow down their falls. A parachute fills up like a balloon, slowing the person down so they fall to the ground gently and safely. People who jump out of planes for fun also use parachutes. When you do this, you're parachuting. Whether for fun or because of your plane's mechanical failure, parachuting is exciting.