During the 1980s the U.S. military wasnt interested in an updated version of the F-16 so they passed on the opportunity. Japan was replacing some of their aging fleet and decided to develop the new F-16 Agile Falcon in cooperation with Mitsubishi and Lockheed Martin. Production began in 1996 with the first aircraft being delivered in 2000. The new aircraft was named the F-2 and soon earned the nickname Viper Zero. Although the F-2 looks similar to the original F-16 it is larger in almost every aspect.