The AIM-9 Sidewinder is a supersonic, heat-seeking air-to-air missile with a high-explosive warhead and a rocket motor, which uses an infrared (IR) guidance system to home in on the heat from a target aircraft's engine exhaust, allowing pilots to launch the missile and then take evasive action.
 
Originally developed by the U.S. Navy and first used in 1956, the Sidewinder is still in active service and has been continuously upgraded, with modern versions like the AIM-9X capable of "all-aspect" targeting.  The Soviet K-13 (AA-2 "Atoll"), a reverse-engineered copy of the AIM-9B, was also widely adopted.
 
The Sidewinder is the most widely used air-to-air missile in the West, with more than 110,000 missiles produced for the U.S. and 27 other nations, of which perhaps one percent have been used in combat. It has been built under license by Sweden and other nations.  The AIM-9 has an estimated 270 aircraft kills.
 
Dimensions: Approximately 16 inches wide by 10.75 inches high; this is a two-page advert.
 
Low-level development started in the late 1940s, emerging in the early 1950s as a guidance system for the modular Zuni rocket. This modularity allowed for the introduction of newer seekers and rocket motors, including the AIM-9C variant, which used semi-active radar homing and served as the basis of the AGM-122 Sidearm anti-radar missile.
 
Due to the Sidewinder's infrared guidance system, the brevity code "Fox Two" is used when firing the AIM-9.  Originally a tail-chasing system, early models saw extensive use during the Vietnam War, but had a low success rate (8% hit rate with the AIM-9E variant).  This led to all-aspect capability in the L (Lima) version, which proved an effective weapon during the 1982 Falklands War and OPERATION MOLE CRICKET 19 in Lebanon. Its adaptability has kept it in service over newer designs like the AIM-95 Agile and SRAAM that were intended to replace it.
 
In 2010, Boeing won a contract to support Sidewinder operations through to 2055.  In 2021 an Air Force spokesperson said that its relatively low cost, versatility, and reliability mean it is "very possible that the Sidewinder will remain in Air Force inventories through the late 21st century".
 
Combat Debut: Taiwan Strait, 1958
The first combat use of the Sidewinder came on 24 September 1958 by the Republic of China (Taiwan) Air Force (ROCAF) during the Second Taiwan Strait Crisis.  At the time, ROCAF North American F-86 Sabres were routinely engaged in air battles with the People's Republic of China over the Taiwan Strait.  In similar fashion to Korean War encounters between the F-86 and earlier MiG-15, high-flying PRC MiG-17s cruised above the ROC Sabres, immune to their .50-cal guns and only fighting when conditions favored them.
 
In a highly secret effort, the United States provided a few dozen Sidewinders to ROC forces and an Aviation Ordnance Team from the U.S. Marine Corps to modify their aircraft to carry the Sidewinder.  In the first encounter on 24 September 1958, ROCAF pilots used the Sidewinders to ambush the MiG-17s as they flew past.  This action marked the first successful use of air-to-air missiles in combat, the downed MiGs being the first casualties.
 
Recent Uses: 2023 North American Balloon & Unidentified Object Shootdowns
On 4 February 2023, an F-22 Raptor operated by the United States Air Force used a single AIM-9X missile to shoot down a suspected Chinese spy balloon off the coast of Surfside Beach, South Carolina at an altitude between 60,000 to 65,000 feet (18,000 to 20,000 m). Six days later, another object was shot down near Alaska.  On 11 and 12 February two more objects were shot down, over Yukon, Canada and Lake Huron in Michigan respectively.
 
Russian Invasion of Ukraine
On 3 May 2025, the head of the Ukrainian Main Directorate of Intelligence (HUR), lieutenant general Kyrylo Budanov claimed that three MAGURA V7 naval drones armed with AIM-9 Sidewinders modified for surface-to-air operation shot down two Russian Su-30 fighter jets in the Black Sea.  The Russian Defense Ministry did not comment, but Russian sources report that the pilots of one fighter were rescued by a cargo ship, whose crew received an award.
 
On September 18, 2025, during a massive missile-drone attack, a video surfaced on social networks showing an F-16 of the Ukrainian Air Force shooting down a Russian Shahed-136 kamikaze drone with an AIM-9L missile.
 
How It Works
Guidance: An IR seeker head in the nose of the missile detects the heat signature of a target aircraft.
Control: The guidance signals are sent to a control assembly that adjusts the fins to steer the missile toward the target.
Launch: A pilot launches the missile, and the IR seeker locks onto the target's heat source. The missile's own internal components and motors provide the power and control needed for it to fly to the target.
Warhead: When the missile gets close enough, an IR proximity fuse detonates the high-explosive warhead, which creates a blast-fragmentation effect to destroy the target.