A jetpack is a device worn on your back that shoots powerful streams of air or hot gases downward, creating thrust that lifts you into the air and lets you fly.

For decades, jetpacks existed mainly in science fiction movies and comic books, where heroes would strap them on and zoom through the sky. Real jetpacks do exist today, but they're extremely expensive, difficult to control, and can only fly for a few minutes before running out of fuel. They work by burning fuel or releasing compressed air so forcefully downward that the reaction pushes the person wearing it upward, following Newton's third law: for every action, there's an equal and opposite reaction.

Despite appearing in countless futuristic predictions, jetpacks never became a practical way to travel. They're too loud, too dangerous, and too fuel-hungry for everyday use. Most modern “jetpacks” are actually used by stunt performers, in military experiments, or by wealthy hobbyists. The dream of everyone jetpacking to school or work remains firmly in the realm of imagination, though engineers keep trying to make better versions.