Airplanes in World War I were made of wood and canvas, a type of rough cloth. They did not last for a long time. They could not fly very fast at the beginning of the war. They could only fly up to 116 kilometers per hour, or 72 miles per hour. At the end of the war they could fly up to . But they could not fly as fast as planes today. Guns were put on planes for the first time during the war. Pilots, people who fly the plane, used the guns to shoot enemy planes. One pilot used metal sheets, pieces of metal, to armor his airplane. Other pilots began using metal sheets, too. Pilots also made their airplanes better with machine guns, guns that shoot bullets much faster. Machine guns made fighting harder and more dangerous between airplanes.