The altitude at which a military aircraft can fly depends partly on the type of aircraft and whether it is “in flight.”
In many respects, the SR-71 “Blackbird” is the fastest piloted aircraft in the world and also holds the record for the highest flight. However, both the X-15 and MiG-25 E-266M also compete for this title. All three military records were established during the arms race of the Cold War in the 1960s and 1970s and have not been broken since, according to Simple Flying. It appears that flying higher has not been a primary focus of military aviation.
SR-71 “Blackbird.” (Photo: Simple Flying)
According to PhysLink.com, most U.S. military aircraft can exceed an altitude of 15,240 meters if they truly make an effort, but their exact limits are mostly classified information. Many wide-body commercial jets have an operational ceiling of 13,106 meters (although they can fly higher). When aircraft ascend higher in Earth’s atmosphere, they require pressurization (like commercial jets) or pilots need to wear pressure suits.
As altitude increases in Earth’s atmosphere, oxygen becomes thinner until there is not enough oxygen in the air to continuously burn jet fuel. Commercial jets typically cruise at altitudes of 9,144 – 13,716 meters (with a maximum altitude of around 12,802 meters). According to the U.S. Air Force, the famous U2 reconnaissance aircraft often flies above 21,366 meters, while PhysLink.com states that the U2 can cruise at altitudes up to 27,432 meters. Stealth bombers typically cruise at around 15,240 meters. The Russian MiG-31 has the highest altitude limit among operational fighter jets today (at 25,000 meters).
The three military aircraft believed to fly at the highest altitudes are the U.S. X-15, the Soviet MiG-25 E-266M, and the U.S. SR-71 Blackbird. Each of these aircraft holds a world record in its respective category. While the records for the MiG-25 E-266M and SR-71 remain unbroken to this day, the civilian SpaceShipOne surpassed the world record of the X-15 in 2004.
X-15
The X-15 is a rocket-powered test aircraft developed collaboratively by the U.S. Air Force and NASA to explore the edge of space. It is the world’s first manned supersonic aircraft and the first to achieve speeds of Mach 4, 5, and 6 (4,939, 6,174, and 7,409 km/h). The vehicle also holds the world record for the fastest manned flight (Mach 6.7 or 8,273 km/h), set in 1967. The X-15 also set the record for the highest manned military flight, reaching 107.8 km in 1963 with pilot Joseph Walker. However, some argue that the X-15 is not strictly an aircraft but rather a rocket with its own oxygen supply.
MiG-25 (E-266M)
According to Smithsonian Magazine, the absolute altitude record belongs to Soviet pilot Alexandr Fedotov, set on August 31, 1977, when he flew the MiG E-266M to an altitude of 37,650 meters. This is the absolute altitude record for an aircraft taking off from the ground and has never been broken. Fedotov passed away on April 4, 1984, while test-flying the MiG-31.
SR-71 “Blackbird”
According to PhysLink.com, the world record for speed and altitude for an aircraft using air-breathing jet engines is 25,949 meters, achieved by the Lockheed SR-71 “Blackbird” in 1976. The SR-71 was designed to cruise at speeds of Mach 3.2 (3,951 km/h) and broke the speed record for horizontal flight at constant altitude (3,529 km/h). The SR-71 can fly at higher speeds and altitudes, but those limits are classified information. NASA states that the SR-71 is the fastest and highest-flying aircraft ever built.
