The F-5E Tiger II was based on the F-5A Freedom Fighter, in comparison to its predecessor, it had larger fuel tanks and new engines, the aircraft was the replacement for all other F-5 variants. All later F-5 variants were based on the F-5E, such as the double seat trainer aircraft F-5F and additional reconnaissance variants.
Even if it was considered as a failure in the United States (the USAF operated only 112 aircraft, and the US-Navy only a few for the Top-Gun movie), the F-5 was exported to many countries (like Ethiopia, Brazil, Chile, Greece, Indonesia, Iran, Jordan, Canada, Morocco, Norway, the Philipines, Saudi Arabia, South Korea, the Switzerland, Taiwan, Thailand, Tunisia, Turkey) so that it became the Flag ship plane of many Air Forces. And it is still operational in some countries.