Fighter aircraft
Technological advances in aerodynamics, propulsion and aerospace building-materials (primarily aluminum alloys) permitted designers to experiment with aeronautical innovations such as swept wings, delta wings, and area-ruled fuselages. Widespread use of afterburning turbojet engines made these the first production aircraft to break the sound barrier, and the ability to sustain supersonic speeds in level flight became a common capability amongst fighters of this generation.
Fighter designs also took advantage of new electronics technologies that made effective radars small enough to carry aboard smaller aircraft. Onboard radars permitted detection of enemy aircraft beyond visual range, thereby improving the handoff of targets by longer-ranged ground-based warning- and tracking-radars. Similarly, advances in guided-missile development allowed air-to-air missiles to begin supplementing the gun as the primary offensive weapon for the first time in fighter history. During this period, passive-homing infrared-guided (IR) missiles became commonplace, but early IR missile sensors had poor sensitivity and a very narrow field of view (typically no more than 30°), which limited their effective use to only close-range, tail-chase engagements. Radar-guided (RF) missiles were introduced as well, but early examples proved unreliable. These semi-active radar homing (SARH) missiles could track and intercept an enemy aircraft "painted" by the launching aircraft's onboard radar. Medium- and long-range RF air-to-air missiles promised to open up a new dimension of "beyond-visual-range" (BVR) combat, and much effort concentrated on further development of this technology.
The prospect of a potential third world war featuring large mechanized armies and nuclear-weapon strikes led to a degree of specialization along two design approaches: interceptors, such as the English Electric Lightning and Mikoyan-Gurevich MiG-21F; and fighter-bombers, such as the Republic F-105 Thunderchief and the Sukhoi Su-7B. Dogfighting, per se, became de-emphasized in both cases. The interceptor was an outgrowth of the vision that guided missiles would completely replace guns and combat would take place at beyond-visual ranges. As a result, strategists designed interceptors with a large missile-payload and a powerful radar, sacrificing agility in favor of high speed, altitude ceiling and rate of climb. With a primary air-defense role, emphasis was placed on the ability to intercept strategic bombers flying at high altitudes. Specialized point-defense interceptors often had limited range and few, if any, ground-attack capabilities. Fighter-bombers could swing between air-superiority and ground-attack roles, and were often designed for a high-speed, low-altitude dash to deliver their ordnance. Television- and IR-guided air-to-surface missiles were introduced to augment traditional gravity bombs, and some were also equipped to deliver a nuclear bomb.

1960s–1970s: Third-generation jet fighters: The third generation witnessed continued maturation of second-generation innovations, but it is most marked by renewed emphases on maneuverability and on traditional ground-attack capabilities. Over the course of the 1960s, increasing combat experience with guided missiles demonstrated that combat would devolve into close-in dogfights. Analog avionics began to appear, replacing older "steam-gauge" cockpit instrumentation. Enhancements to the aerodynamic performance of third-generation fighters included flight control surfaces such as canards, powered slats, and blown flaps. A number of technologies would be tried for vertical/short takeoff and landing, but thrust vectoring would be successful on the Harrier.
Growth in air-combat capability focused on the introduction of improved air-to-air missiles, radar systems, and other avionics. While guns remained standard equipment (early models of F-4 being a notable exception), air-to-air missiles became the primary weapons for air-superiority fighters, which employed more sophisticated radars and medium-range RF AAMs to achieve greater "stand-off" ranges, however, kill probabilities proved unexpectedly low for RF missiles due to poor reliability and improved electronic countermeasures (ECM) for spoofing radar seekers. Infrared-homing AAMs saw their fields of view expand to 45°, which strengthened their tactical usability. Nevertheless, the low dogfight loss-exchange ratios experienced by American fighters in the skies over Vietnam led the U.S. Navy to establish its famous "TOPGUN" fighter-weapons school, which provided a graduate-level curriculum to train fleet fighter-pilots in advanced Air Combat Maneuvering (ACM) and Dissimilar air combat training (DACT) tactics and techniques.
This era also saw an expansion in ground-attack capabilities, principally in guided missiles, and witnessed the introduction of the first truly effective avionics for enhanced ground attack, including terrain-avoidance systems. Air-to-surface missiles (ASM) equipped with electro-optical (E-O) contrast seekers – such as the initial model of the widely used AGM-65 Maverick – became standard weapons, and laser-guided bombs (LGBs) became widespread in an effort to improve precision-attack capabilities. Guidance for such precision-guided munitions (PGM) was provided by externally-mounted targeting pods, which were introduced in the mid-1960s.
The third generation also led to the development of new automatic-fire weapons, primarily chain-guns that use an electric motor to drive the mechanism of a cannon. This allowed a plane to carry a single multi-barrel weapon (such as the 20 mm (0.79 in) Vulcan), and provided greater accuracy and rates of fire. Powerplant reliability increased, and jet engines became "smokeless" to make it harder to sight aircraft at long distances.
Dedicated ground-attack aircraft (like the Grumman A-6 Intruder, SEPECAT Jaguar and LTV A-7 Corsair II) offered longer range, more sophisticated night-attack systems or lower cost than supersonic fighters. With variable-geometry wings, the supersonic F-111 introduced the Pratt & Whitney TF30, the first turbofan equipped with afterburner. The ambitious project sought to create a versatile common fighter for many roles and services. It would serve well as an all-weather bomber, but lacked the performance to defeat other fighters. The McDonnell F-4 Phantom was designed to capitalize on radar and missile technology as an all-weather interceptor, but emerged as a versatile strike-bomber nimble enough to prevail in air combat, adopted by the U.S. Navy, Air Force and Marine Corps. Despite numerous shortcomings that would not be fully addressed until newer fighters, the Phantom claimed 280 aerial kills (more than any other U.S. fighter) over Vietnam. With range and payload capabilities that rivaled that of World War II bombers such as B-24 Liberator, the Phantom would become a highly successful multirole aircraft.

1970s–2000s: Fourth-generation: Fourth-generation fighters continued the trend towards multirole configurations, and were equipped with increasingly sophisticated avionics- and weapon-systems. Fighter designs were significantly influenced by the Energy-Maneuverability (E-M) theory developed by Colonel John Boyd and mathematician Thomas Christie, based upon Boyd's combat experience in the Korean War and as a fighter-tactics instructor during the 1960s. E-M theory emphasized the value of aircraft-specific energy maintenance as an advantage in fighter combat. Boyd perceived maneuverability as the primary means of getting "inside" an adversary's decision-making cycle, a process Boyd called the "OODA loop" (for "Observation-Orientation-Decision-Action"). This approach emphasized aircraft designs capable of performing "fast transients" – quick changes in speed, altitude, and direction – as opposed to relying chiefly on high speed alone.
E-M characteristics were first applied to the McDonnell Douglas F-15 Eagle, but Boyd and his supporters believed these performance parameters called for a small, lightweight aircraft with a larger, higher-lift wing. The small size would minimize drag and increase the thrust-to-weight ratio, while the larger wing would minimize wing loading; while the reduced wing loading tends to lower top speed and can cut range, it increases payload capacity and the range reduction can be compensated for by increased fuel in the larger wing. The efforts of Boyd's "Fighter mafia" would result in the General Dynamics F-16 Fighting Falcon (now Lockheed Martin's).
The F-16's maneuverability was further enhanced by its slight aerodynamic instability. This technique, called "relaxed static stability" (RSS), was made possible by introduction of the "fly-by-wire" (FBW) flight-control system (FLCS), which in turn was enabled by advances in computers and in system-integration techniques. Analog avionics, required to enable FBW operations, became a fundamental requirement, but began to be replaced by digital flight-control systems in the latter half of the 1980s. Likewise, Full Authority Digital Engine Controls (FADEC) to electronically manage powerplant performance was introduced with the Pratt & Whitney F100 turbofan. The F-16's sole reliance on electronics and wires to relay flight commands, instead of the usual cables and mechanical linkage controls, earned it the sobriquet of "the electric jet". Electronic FLCS and FADEC quickly became essential components of all subsequent fighter designs.