Military aircraft are capable of flying at high altitudes, but the specific altitude limits depend on several factors. During the Cold War arms race in the 1960s and 1970s, records for the highest flights were set by aircraft like the SR-71 Blackbird, X-15, and MiG E-266M, which remain unbeaten to this day. While these records are impressive, flying at high altitudes is not always a primary focus of military aviation.
Most US military aircraft can exceed an altitude of 15,240 m and have specific altitude limits classified. Commercial jets typically have an altitude limit around 13,106 m but can fly higher when pressurized or equipped with pressurized suits for pilots. As aircraft climb higher in the atmosphere, oxygen levels decrease, requiring pressurization for both the aircraft and crew.
The U2 reconnaissance aircraft flies at altitudes exceeding 21,366 m while commercial jets usually operate between 9,144 and 13,716 m. The Russian MiG-31 holds the record for the highest altitude limit of any fighter currently in operation at 25,000 m. Stealth bombers maintain a cruising altitude of 15,240 m.
Three military aircraft stand out for their high-altitude capabilities – the X-15, MiG-25 E-266M and SR-71 Blackbird. Each of these aircraft set world records during their time. The X-15 was the first manned supersonic aircraft and first to reach speeds exceeding Mach 4, 5 and 6. The MiG-25 E-266M flown by Soviet pilot Alexandr Fedotov reached an unmatched altitude of 37,650 m while Lockheed SR-71 Blackbird achieved a world record for speed and altitude in 1976 reaching heights of 25,949 m. These feats represent remarkable achievements in aviation history
