The P-38 Lightning is a World War II fighter aircraft made by Lockheed. It was mainly used by the United States Air Force. It first flew in 1939. It was different from other fighters because it had two engines instead of one, and was twice the size of other fighters. The plane fought in the Pacific and in Europe. It could carry 4 machine guns and a cannon. By 1944, it was replaced by the faster P-51 Mustang in Europe. The P-38 was the only American fighter being built at the beginning and the end of the war.