The F-16 Fighting Falcon was produced by General Dynamics who became Lockheed who then merged with Martin Marietta to become Lockheed Martin. The F-16 entered service in January 1979 as a multi-role jet fighter that evolved into an all-weather multi-role aircraft capable of sustaining 9-g turns. The F-16 is relatively inexpensive to purchase and maintain so the U.S. and 25 other countries added it to their inventory. The Fighting Falcon is referred to by its pilots as the "Viper"; and will remain in USAF service until 2025.