Taiwan is retiring its remaining F-5 fighters. Taiwan began receiving F-5s in the 1970s and once had 66 in service. But accidents and old age reduced that to 32 now and these are used mostly for training. The F-5s is a 12 ton fighter roughly similar to the 1950s era MiG-21, and is a contemporary of that Russian fighter. The F-5 was built mainly for export to nations that could not afford the top-line Western fighters, but did not want the MiG-21s. The F-5 is normally armed with two 20mm cannon, and three tons of missiles and bombs. Introduced in 1962, over 2,200 were built before production ended in 1987.
Taiwan began receiving more modern fighters, like the F-16 and Mirage 2000 in the 1990s, along with a locally made fighters that was somewhere between the F-5 and F-16 in capabilities. As China began to receive more modern fighters (like the Su-27 and Su-30 and Chinese built clones of those) in the 1990s Taiwan decided that even upgrading the F-5s to deal with Su-30 class fighters was not worth the effort. Some F-5 users disagreed. Brazil still maintains a force of F-5s, upgraded to a local variant called the F-5EM. This one has modern electronics, making it capable to using long range air-to-air missile (the Israeli radar guided Derby, in addition to the heat-seeking Derby). A look-and-shoot helmet is also part of the upgrade. There is only one 20mm cannon left, but lots of missiles and smart bombs.
The F-5 proved itself superior in combat versus the MiG-21 although there were no combat encounters between F-5s and the 21st century models of the much improved and upgraded MiG-21s. While the F-5 ceased production in 1987 MiG-21s continued to be built until 2013. This was actually a Chinese clone called the J7. Over 2,400 J7s were produced over half a century. China began licensed production of the Russian MiG-21 in 1964, but it took another decade for that to evolve into the J7 and for mass production to really get started. The earlier ones were inferior to the MiG-21 because Russia refused to transfer technology for the latest models of this 1950s design. By the 1980s the Chinese had matched the Russian MiG-21. This didn’t bother the Russians because in 1985 Russia ceased production, after more than 11,000 had been produced. From then on, if you wanted a new MiG-21 you had only one source, the Chinese J7. In the last three decades China kept improving the J7 capabilities, mainly through tweaks to the airframe and better electronics. Most J7s were used by China but about twenty percent were exported to fourteen countries. About a dozen of these nations still operate their J7s. In 2011 China officially withdrew its J7s from first line service. This came as no surprise. Between 2007 and 2011 China more than doubled the number of modern combat aircraft (J-10, J-11, Su-27, Su-30, and J8F) from 500 to over 1,200. As recently as 2007 China relied mainly on some 2,000 locally built copies of Russian MiG-19s (J6) and MiG-21s (J7).
China has long been the largest user of the MiG-21/J7. China continued to export J7s until 2013 but was rapidly retiring the ones remaining in Chinese service. The J7 was, in many ways, the most advanced version of the MiG-21, as the Chinese kept improving their J7 design. Over 13,000 Mig-21s and J7s have been produced in the last sixty years, making this the most widely manufactured jet fighter of the last century. During World War II there were several propeller driven fighters that were produced in greater numbers, but once jets appeared in combat it was clear where the future was.
The MiG-21 looked fearsome but it was a bust in combat, getting shot down more often than not. Russia still had 186 Mig-21s in service when the Soviet Union dissolved in 1991. These MiG-21s were officially retired a few years later. India, the last major user of the MiG-21, is in the process of retiring them as well. The F-5, however, continues in active service in several air forces. Unlike the MiG-21, which was built to be used little in peace time and then employed vigorously, if briefly, in wartime, the F-5 was built to be used a lot for training in peace time. This was, until the MiG-29 and Su-27 came along in the 1980s, a major difference between Western and Russian warplanes.