The Lockheed Martin/Boeing F-22 Raptor is an American twin-engine, jet-powered, all-weather, supersonic stealth fighter aircraft. As a product of the United States Air Force's Advanced Tactical Fighter (ATF) program, the aircraft was designed as an air superiority fighter, but also incorporates ground attack, electronic warfare, and signals intelligence capabilities. The prime contractor, Lockheed Martin, built most of the F-22 airframe and weapons systems and conducted final assembly, while program partner Boeing provided the wings, aft fuselage, avionics integration, and training systems.

First flown in 1997, the F-22 descended from the Lockheed YF-22 and was variously designated F-22 and F/A-22 before it formally entered service in December 2005 as the F-22A. It replaced the F-15 Eagle in most active duty U.S. Air Force (USAF) squadrons. Although the service had originally planned to buy a total of 750 ATFs to replace its entire F-15 fleet, it later scaled down to 381 and the program was ultimately cut to 195 aircraft – 187 of them operational models – in 2009 due to political opposition from high costs, a perceived lack of air-to-air threats at the time of production, and the development of the more affordable and versatile F-35 Lightning II. The last aircraft was delivered in 2012.

The F-22 is a critical component of the USAF's tactical airpower as its most advanced air superiority fighter. While it had a protracted development and initial operational difficulties, the aircraft became the service's leading counter-air platform. Its deployments include Okinawa, the Middle East, and NATO's eastern flank. Although designed for air superiority operations, the F-22 has also carried out and supported airstrikes. The F-22 is expected to remain a cornerstone of the USAF's fighter fleet until its succession by the Boeing F-47 expected around 2030.

The F-22 originated from the Advanced Tactical Fighter (ATF) program that the U.S. Air Force (USAF) initiated in 1981 to replace the F-15 Eagle and F-16 Fighting Falcon. Intelligence reports indicated that their effectiveness would be eroded by emerging worldwide threats emanating from the Soviet Union, including new developments in surface-to-air missile systems for integrated air defense networks, the introduction of the Beriev A-50 "Mainstay" airborne warning and control system (AWACS), and the proliferation of the Sukhoi Su-27 "Flanker" and Mikoyan MiG-29 "Fulcrum" class of fighter aircraft. Code-named "Senior Sky", the ATF would become an air superiority fighter program influenced by these threats; in the potential scenario of a Soviet and Warsaw Pact invasion in Central Europe, the ATF was envisaged to support the air-land battle by spearheading offensive and defensive counter-air operations (OCA/DCA) in this highly contested environment that would then enable following echelons of NATO strike and attack aircraft to perform air interdiction against ground formations; to do so, the ATF would make an ambitious leap in capability and survivability by taking advantage of the new technologies in fighter design on the horizon, including composite materials, lightweight alloys, advanced flight control systems and avionics, more powerful propulsion systems for supersonic cruise (or supercruise) around Mach 1.5, and stealth technology for low observability.

The USAF published an ATF request for information (RFI) to the aerospace industry in May 1981, and following a period of concept and specification development, the ATF System Program Office (SPO) issued the demonstration and validation (Dem/Val) request for proposals (RFP) in September 1985, with requirements placing strong emphasis on stealth, supersonic cruise and maneuver. The RFP saw some alterations after its initial release, including more stringent signature reduction requirements in December 1985 and the addition of the requirement for flying technology demonstrator prototypes in May 1986. Owing to the immense investments required to develop the advanced technologies, teaming among companies was encouraged. Of the seven bidding companies, Lockheed and Northrop were selected on 31 October 1986 as Dem/Val finalists. Lockheed, through its Skunk Works division at Burbank, California, teamed with Boeing and General Dynamics while Northrop teamed with McDonnell Douglas. These two contractor teams undertook a 50-month Dem/Val phase to compete for ATF full-scale development, culminating in the flight test of two technology demonstrator prototypes, the Lockheed YF-22 and Northrop YF-23; while they represented competing designs, the prototypes were meant for demonstrating concept viability and risk mitigation rather than a competitive flyoff. Concurrently, Pratt & Whitney and General Electric competed for the ATF engines.

Dem/Val was focused on system engineering, technology development plans, and risk reduction over point aircraft designs; in fact, after down-select, the Lockheed team completely redesigned the airframe configuration in summer 1987 due to weight analysis, with notable changes including the wing planform from swept trapezoidal to diamond-like delta and a reduction in forebody planform area. The team extensively used analytical and empirical methods including computational fluid dynamics and computer-aided design, wind tunnel testing (18,000 hours for Dem/Val), and radar cross-section (RCS) calculations and pole testing. Avionics were tested in ground prototypes and flying laboratories. During Dem/Val, the SPO used trade studies from both teams to review the ATF system specifications and adjust or delete requirements that were significant weight and cost drivers while having marginal value. The short takeoff and landing (STOL) requirement was relaxed to delete thrust-reversers, saving substantial weight. Side looking radars and the dedicated infrared search and track (IRST) system were eventually removed as well, although space and cooling provisions were retained to allow for their later addition. The ejection seat was downgraded from a fresh design to the existing ACES II. Despite efforts by both teams to rein in weight, the takeoff gross weight estimates grew from 50,000 to 60,000 lb (22,700 to 27,200 kg), resulting in engine thrust requirement increasing from 30,000 to 35,000 lbf (133 to 156 kN) class.

Each team built two prototype air vehicles for Dem/Val, one for each engine option. The YF-22 had its maiden flight on 29 September 1990 and, in testing, successfully demonstrated supercruise, high angle-of-attack maneuvers, and the firing of air-to-air missiles from internal weapons bays. After the flight test of the demonstrator prototypes at Edwards Air Force Base, the teams submitted the results and their full-scale development design proposals – or Preferred System Concept – in December 1990; on 23 April 1991, the Secretary of the USAF, Donald Rice, announced the Lockheed team and Pratt & Whitney as the winners of the ATF and engine competitions. Both designs met or exceeded all performance requirements; the YF-23 was considered stealthier and faster, but the YF-22, with its thrust vectoring nozzles, was more maneuverable as well as less expensive and risky, having flown considerably more test sorties and hours than its counterpart. The press also speculated that the Lockheed team's design was more adaptable to the Navy Advanced Tactical Fighter (NATF) for replacing the F-14 Tomcat, but by fiscal year (FY) 1992, the U.S. Navy had abandoned NATF due to cost.

The program formally moved to full-scale development, or Engineering & Manufacturing Development (EMD), in August 1991. The production F-22 design (internally designated Configuration 645) had also evolved to have notable differences from the YF-22, which was immature due to being frozen relatively soon after the complete redesign in the summer of 1987. While the overall layout was similar, the external geometry saw significant alterations; the wing's leading edge sweep angle was decreased from 48° to 42°, while the vertical stabilizers were shifted rearward and decreased in area by 20%. The radome shape was changed for better radar performance, the wingtips were clipped for antennas, and the dedicated airbrake was eliminated. To improve pilot visibility and aerodynamics, the canopy was moved forward 7 inches (18 cm) and the engine inlets moved rearward 14 inches (36 cm). The shapes of the fuselage, wing, and stabilator trailing edges were refined to improve aerodynamics, strength, and stealth characteristics. The internal structural design was refined and reinforced, with the production airframe designed for a service life of 8,000 hours. The revised shaping was validated with over 17,000 additional hours of wind tunnel testing and further RCS testing at Helendale, California and the USAF RATSCAT range before the first flight. Increasing weight during EMD due to demanding ballistic survivability requirements and added capabilities caused slight reductions in projected range and maneuver performance.