A jet airplane is an aircraft powered by jet engines, which work by sucking in air, compressing it, mixing it with fuel, and igniting it to create a powerful blast of hot gas that shoots out the back. This blast pushes the plane forward at tremendous speeds, the same way a balloon rockets around a room when you let the air rush out.

Jet airplanes revolutionized travel when they became common in the 1950s and 1960s. Before jets, propeller planes were much slower: a trip from New York to London took 15 hours or more. Jets cut that time to about 7 hours. Today, a jet can carry hundreds of passengers across an ocean at speeds over 500 miles per hour, flying so high (often around 35,000 feet) that the air is too thin to breathe without a pressurized cabin.

When people say they're “taking a jet” somewhere or flying on a “jumbo jet,” they're usually talking about commercial airliners. Fighter jets are smaller, faster military aircraft. Private jets carry just a few passengers in luxury.