The prolific MiG-21 series has seen service all over the world, and about fifteen thousand have been produced in 15 major and 100 minor versions. It is a classic Soviet design: simple and inexpensive to build and maintain. Thus its strength lies in its ability to be built and fielded in large numbers rather than high-performance. It is a "no-frills" fighter, with no great strengths and no major weaknesses (for its day) apart from an inability to withstand battle damage. Earliest models entered service in 1959, and were the first Soviet aircraft to carry air-to-air missiles as a standard weapon. It was also the first Soviet aircraft able to reach Mach 2, yet unlike the F-104 it maintained good agility. The 'F' model is one of the oldest MiG-21 types still in use. It is totally obsolete, but still used by many countries (though often in the role of fighter-bomber).
