The C-5 Galaxy is a very big military cargo aircraft made by Lockheed (now Lockheed Martin) used by the United States Air Force. It first flew in 1968 and was introduced in 1970. It is one of the biggest transports in the world. It is 247 feet (75 meters) long, 65 feet (19 meters) high, has a wingspan of 222 feet (67 meters), and can weigh up to 840,000 pounds (378,000 kilograms).