Two missile families decide most modern air combat: the short-range, heat-seeking AIM-9 Sidewinder and its peers for the dogfight, and the long-range, active-radar AIM-120 AMRAAM and its peers for the beyond-visual-range engagement. The guidance method matters more than the warhead, and the no-escape zone matters more than the headline range.
See the AIM-120 AMRAAM in the galleryAir-to-air missiles divide cleanly into two classes by intended engagement range. Within visual range (WVR) missiles are short, light, and highly manoeuvrable; the pilot can see the target and cues the seeker with eyeballs or a helmet sight. Beyond visual range (BVR) missiles are larger, fly higher and faster, and rely on the launching aircraft's radar — or their own — to find a target the pilot may never see optically.
The WVR/BVR split also corresponds to seeker technology. WVR weapons use infrared homing — they chase heat. BVR weapons used to use semi-active radar homing, but today almost all of them use active radar homing, where the missile's own onboard radar finds the target in the final seconds of flight.
An infrared seeker stares at a narrow patch of sky through a glass dome and looks for heat sources brighter than the background. The first AIM-9 Sidewinder, the AIM-9B, entered service in 1956 and could only see hot exhaust pipes — meaning it had to be fired from the rear quarter of the target, inside a narrow cone behind the engine. Hit probability against a manoeuvring target was low; in Vietnam, AIM-9B Pk against actively defending MiGs ran around 15%.
Every later generation widened the engagement envelope:
The Russian counterpart line runs K-13 (a 1958 copy of the AIM-9B), R-60, and the all-aspect R-73 (1985) which set the bar for off-boresight engagement. The European ASRAAM uses an imaging seeker similar to the AIM-9X but with a 50% larger motor for ranges out to roughly 25 km. The Israeli Python-5 introduced lock-on after launch independently in the late 1990s.
Flares burn at 1,500-2,000°C — hotter than a jet exhaust at 600-700°C — and are released in patterns timed to drag an IR seeker's tracking gate off the aircraft. Imaging seekers defeat this by recognising the aircraft's shape rather than just its hottest point. An AIM-9X focal-plane array sees a 128 × 128 pixel thermal image and ignores any heat source that does not match an aircraft silhouette. This is called infrared counter-countermeasures (IRCCM), and it is the reason mid-1990s and later WVR missiles are difficult to spoof.
A semi-active radar-homing (SARH) missile has no radar of its own — only a receiver. The launching fighter's radar must illuminate the target with a continuous wave for the entire missile time of flight. The AIM-7 Sparrow family worked this way from 1958 through the AIM-7M (1982), as did the AIM-54 Phoenix in its mid-course phase. The Russian R-27R is SARH.
The fatal weakness of SARH: the launching fighter has to point its radar at the target all the way to impact. Against a four-ship of MiGs at 60 km, that means committing the radar to one target for 60 seconds while the other three close and shoot back. SARH is almost extinct in front-line Western inventories — the last F-15 squadrons retired AIM-7M around 2024.
The AIM-120 AMRAAM entered service in 1991 and changed BVR combat. The missile carries a small X-band active radar in its nose. The launching fighter provides mid-course guidance via a one-way datalink — small radio updates that nudge the missile toward the predicted target position. When the missile is close enough to acquire on its own, the seeker activates and homes terminally. The launching fighter is free to manoeuvre or engage another target.
The AMRAAM family has run through three production phases:
The Russian R-77 family is the AMRAAM counterpart. The RVV-AE (export R-77, 1994) used unusual lattice fins for compactness; the R-77-1 (2010) replaced them with conventional fins, lengthened the motor, and added an improved seeker. The PRC-developed PL-15 goes further — a dual-pulse motor variant pushes claimed range past 200 km, and a ramjet-powered PL-21 derivative is reported to extend further.
A solid-rocket motor burns for a few seconds and then coasts. By the end of its flight, an AMRAAM has lost most of its kinetic energy and can struggle to chase a target that turns away at the right moment. The MBDA Meteor solves this with a throttleable solid-fuel ramjet that produces thrust for the entire flight. Meteor leaves the rail at Mach 4+, sustains energy through long mid-course phases, and is widely reported to maintain a no-escape zone three to five times larger than the AIM-120D's at any equivalent launch range. The Eurofighter Typhoon, Rafale F3R, and Gripen E/F all carry it; the F-35 cleared Meteor integration in 2024.
The Russian R-37M is a different long-range BVR weapon — a 510 kg, Mach 6, solid-fuel missile with a claimed 200+ km range, designed originally for the MiG-31BM but cleared for the Su-35 and Su-57. It is not a ramjet, but its sheer kinematic mass gives it a long no-escape zone against high, fast targets such as AWACS and tankers.
Maximum range is the headline number, but it assumes a co-operative non-manoeuvring target flying straight at the shooter at high altitude. Real combat ranges are far shorter. The number that matters is the no-escape zone (NEZ) — the launch envelope inside which a target turning 180 degrees and running cannot kinematically defeat the missile.
For an AIM-120D launched head-on at a Mach 0.9 target at 30,000 ft, the headline maximum range may be 160 km, but the NEZ is closer to 40-50 km. The Meteor's no-escape zone in the same setup is widely cited at 100+ km — the ramjet keeps producing thrust while the target tries to disengage. Inside the NEZ, the only options are jamming, flares (worthless against active radar), or aggressive last-second manoeuvring at high G.
Pre-1985, an IR missile could only engage what was directly in front of the launching fighter — within the seeker's narrow forward cone before launch. The R-73 on the MiG-29 changed this. The Russian Shchel helmet-mounted sight let the pilot turn his head, place the helmet reticule on a target up to 60 degrees off boresight, and slave the R-73's seeker to look there before launch. The missile would acquire and fire while the launching aircraft was still pointing somewhere else.
Western forces took fifteen years to match this. The Joint Helmet Mounted Cueing System (JHMCS) on the F-15, F-16, and F/A-18 entered service from 2003 and pairs with the AIM-9X for off-boresight engagement. The F-35's Gen III HMDS goes further: the helmet itself is the primary display, and the pilot can cue the AIM-9X (or look-back-and-shoot via the Distributed Aperture System cameras) without any heads-up display at all.
An active-radar missile's seeker is small and short-ranged — typically able to acquire a target only inside about 15-20 km. For long-range shots, the launching fighter must guide the missile through the first 80-90% of its flight via a mid-course datalink. The AIM-120's link is a narrow one-way burst from the launching fighter's radar; the AIM-120D added two-way return data so the missile can report its track and energy state.
This opens up networked engagements. An AWACS aircraft can hand a target track to a fighter via Link 16; the fighter launches an AMRAAM; another fighter, or the AWACS itself, provides the mid-course updates while the shooter turns away. The F-22 and F-35 can also pass tracks to each other via the IFDL and MADL stealth-compatible datalinks — letting one aircraft stay silent and emissions-cold while another's missile flies on its track. See What Is AWACS? for the airborne controller side of this.
Content adapted from publicly available aeronautical engineering and defence references. Vehicle data sourced from the Who That Plane?! gallery.