Russia Tried to Replace the MiG-31 Five Times. The 50-Year-Old Foxhound Outlived Them All

Russia has spent more than 30 years trying to replace the MiG-31 Foxhound, but every serious successor program has failed before reaching full service. The jet—first flown on September 16, 1975 and entering service in 1981—remains in active duty as a 50-year-old interceptor protecting Russian airspace, after more than 500 aircraft were built by the mid-1990s. A major step toward replacement, the MiG-31M, was considered ready for production following a record missile shot in 1994, but it was canceled after the post-Soviet budget collapse. Subsequent concepts and projects, including clean-sheet designs and satellite-killer variants, also ended without replacement hardware, while the long-promised MiG-41 still shows no visible prototype. Today, upgraded MiG-31BM and MiG-31K aircraft continue to guard airspace and launch long-range missiles, including Kinzhal weapons, leaving the Foxhound without a true competitor.