Classification of Fighter Aircraft: A Generation-by-Generation Look
Fighter jets are categorized into different generations based on their features, capabilities, performance, and year of development. This method of classification is a broad concept with hazy demarcation lines. Although dependent upon the advancement of technology, it does not define specific features or capabilities and leaves large scope for differences of opinion. Understanding the evolution of these incredible machines provides insight into the history and future of aerial warfare technology. This look at the Generation Of Fighter Aircraft explores how these platforms have evolved over time.
The origin of the generational categorization of jet combat aircraft is debatable. Usage appears to have first surfaced in Russia during the mid-1990s when officials were planning a competitor to the American Joint Strike Fighter. They categorized previous fighters into four groups and concluded that the next one would be in the fifth generation. Aviation Week correspondent Bill Sweetman claims it originated within Lockheed Martin’s business development machine shortly after the X-35 was declared the successful JSF solution in 2001.
Previous attempts at classifying jet fighters exist. In 1990, air historian Richard P. Hallion proposed a classification into six generations up to that time. Others classified them into five generations around the same period. Taylor and Guilmartin named four classifications based on maximum speed – subsonic, transonic, supersonic, and Mach 2 – and added a fifth “new” generation with multi-mission capability. Russian and Chinese observers also categorize aircraft into generations, albeit with differing and broader definitions across fewer generations that relate more towards their platforms and capabilities.
Relevant aspects of this classification include:
- This method of categorization is unofficial, as there is no authorized concept based on specific features or performance criteria.
- There is no clearly defined line between successive generations. Different authorities have identified different technology jumps as the key ones, leading to various numbering of generations.
- Each category represents a certain class of technology used in the aircraft, including avionics, systems, design, features, engines, and weapons. A higher generation signifies a more technologically advanced aircraft.
- A generational shift in jet fighter aircraft typically occurs when a technological innovation cannot be effectively incorporated into an existing aircraft through upgrades and retrospective fit-outs.
- The criteria for the various generations are not universally accepted and are subject to differing opinions among experts and observers.
Generations of Fighter Jets
Accepted Classification Norms
In 2004, Aerospaceweb listed a division into five generations. This basic classification into five generations has since become widely accepted. Five generations are now commonly recognized, with the development of a sixth underway. Some accounts have subdivided the 4th generation into 4 and 4.5, or 4+ and 4++. To compare 4th generation fighter aircraft requires understanding these sub-classifications.
First Generation Subsonic Jet Fighters (mid-1940s to mid-1950s)
This category comprises the earliest subsonic jet fighters that appeared during and after the last years of World War II. They were similar in most aspects to their piston-engined contemporaries, often having straight wings and being of wood and/or light alloy construction. The main feature of the Gen 1 fighter was its significant advance in speed over piston-engine predecessors. The introduction of the swept wing allowed transonic speeds to be reached, but controllability was often limited at such speeds. These early jet engines did not have afterburners, and the aircraft primarily operated in the subsonic regime. They had basic avionic systems, no radars or self-protection countermeasures, and were typically armed with machine guns or cannons, as well as unguided bombs and rockets. These aircraft were typically aimed at the air-superiority interceptor role.
First Generation Fighter Jets
According to available open sources, fighters in this generation could include:
- Messerschmitt Me 262 Schwalbe
- Heinkel He 162 Salamander
- Messerschmitt Me 163 Komet
- Gloster Meteor
- de Havilland Vampire
- de Havilland Venom
- Hawker Siddeley/Armstrong Whitworth Sea Hawk
- Supermarine Attacker
- Supermarine Swift
- Lockheed P-80 (F-80) Shooting Star
- Republic F-84 Thunderjet / Thunderstreak
- North American F-86 Sabre
- Northrop F-89 Scorpion
- Lockheed F-94 Starfire
- McDonnell FH-1 Phantom
- Vought F6U Pirate
- Vought F7U Cutlass
- North American FJ (F-1) Fury
- McDonnell F2H (F-2) Banshee
- McDonnell F3H (F-3) Demon
- Douglas F4D (F-6) Skyray
- Grumman F9F (F-9) Panther / Cougar
- Douglas F3D (F-10) Skyknight
- Mikoyan Gurevich MiG-15
- Mikoyan Gurevich MiG-17
- Lavochkin La-15
- Yakovlev Yak-15
- Yakovlev Yak-17
- Yakovlev Yak-23
- Dassault Ouragan
- Dassault Mystère
- Saab J21R
- Saab J29
- Saab Lansen
- Avro Canada CF-100 Canuck
Second Generation Jet Fighters (mid-1950s to early 1960s)
The second generation of fighter jets resulted from technological breakthroughs and experience gained during early aerial warfare, notably the Korean War. The main features included higher speed (sustained transonic and supersonic dash capabilities), the introduction of rudimentary fire control radar, and the first use of guided air-to-air missiles. This generation’s fighters also incorporated advances in engine design (afterburners) and aerodynamics (more sophisticated swept wings), which allowed them to reach and sustain supersonic speeds in level flight. Second generation fighters saw the introduction of early air-to-air radar, infrared, and semi-active radar-guided missiles, as well as radar warning receivers. During this period, although air-to-air combat was still largely within visual range, radar-guided missiles started to extend engagement ranges and accuracy. Aircraft began to be more distinctly divided according to their roles, such as Interceptors (e.g., MiG-21F, SU-9, F-106) and fighter-bombers (e.g., F-105, SU-7) focused on air superiority or ground attack.
According to available open sources, fighters in this generation could include:
- North American F-100 Super Sabre
- McDonnell F-101 Voodoo
- Convair F-102 Delta Dagger
- Lockheed F-104 Starfighter
- Republic F-105 Thunderchief
- Convair F-106 Delta Dart
- Vought F8U (F-8) Crusader
- Grumman F11F (F-11) Tiger
- Mikoyan Gurevich MiG-19
- Mikoyan Gurevich MiG-21
- Sukhoi Su-9 / Su-11
- Yakovlev Yak-25
- BAC Lightning
- de Havilland Sea Vixen
- Gloster Javelin
- Hawker Hunter
- Supermarine Scimitar
- Dassault Étendard
- Dassault Mirage III
- Saab Draken
Third Generation Jet Fighters (early 1960s to 1970)
The Third generation of fighters were designed with multirole capabilities in mind, aiming to perform both air defence and ground attack missions. They could carry a wider range of weapons and other ordnance, such as early air-to-ground missiles and laser-guided bombs, while also being able to engage in air-to-air interception beyond visual range. These aircraft were often capable of sustained supersonic flight, carried improved fire control radars and semi-active air-to-air missiles, and featured the first generation of tactical electronic warfare systems. The advent of more economical turbofan engines brought extended range and sortie times, increased thrust, better performance, and manoeuvrability. Some designers even resorted to variable geometry or vectored thrust to enhance performance. This generation witnessed significant enhancements in avionic suites and weapon systems. Supporting avionics included pulse-doppler radar, early off-sight targeting, and terrain-warning systems. Doppler radar supported a ‘look-down / shoot-down’ capability. With off-bore-sight targeting and semi-active guided radio frequency missiles, these aircraft marked a major change: it was no longer strictly necessary to visually acquire opponents to neutralize them and gain control of the air. Determining the number of fighter aircraft India possesses involves looking at the composition of different generations in its inventory.
According to available open sources, fighters in this generation could include:
- McDonnell Douglas F-4 Phantom II
- General Dynamics F-111 Aardvark
- Mikoyan Gurevich MiG-23
- Mikoyan Gurevich MiG-25
- Sukhoi Su-15
- Sukhoi Su-17 / Su-20 / Su-22
- Tupolev Tu-28
- Yakovlev Yak-28
- Shenyang J-8
- Dassault Mirage F1
- Saab Viggen
- Chengdu J-7
- IAI Kfir
- English Electric Lightning
- BAC TSR-2
Fourth Generation Jet Fighters (1970 to late 1980s)
These fighters debuted in the mid-1970s and remain in use in many air forces globally. This generation is the longest of the generally accepted classifications so far. Fourth generation fighter jets are largely multirole aircraft with the ability to rapidly switch roles between air-to-air and air-to-ground missions, blurring the distinction seen in previous role-dedicated aircraft. The introduction of fly-by-wire control systems improved the manoeuvrability of these aircraft, sometimes at the expense of inherent aerodynamic stability which was then compensated for by the control system. These aircraft introduced more efficient and powerful turbofan jet engines, often allowing thrust-to-weight ratios greater than one, which significantly enhanced performance in a dogfight. While composite materials were used, revolutionizing stealth technology would primarily feature in the next generation. Electronics became increasingly essential, including ‘look-down’ doppler fire-control radars, advanced fly-by-wire flight control systems, integral and podded EO/IR targeting sensors, laser and GPS-guided precision weapons, active air-to-air missiles, heads-up displays, and improved electronic warfare systems. The F-16, often referred to as the fighting falcon aircraft, is a prime example of a highly successful fourth-generation design.
According to available open sources, fighters in this generation could include:
- Grumman F-14 Tomcat
- McDonnell Douglas F-15 Eagle
- General Dynamics F-16 Fighting Falcon
- McDonnell Douglas F/A-18 Hornet
- Mikoyan MiG-29 Fulcrum
- Mikoyan MiG-31 Foxhound
- Sukhoi Su-27 Flanker
- Sukhoi Su-33 Flanker-D
- Dassault Mirage 2000
- Panavia Tornado
- Saab JAS 39 Gripen (early variants)
- Mitsubishi F-2
Four and Half Generation Jet Fighters (late 1980s and into the 90s)
The concept of a half-generation increment stemmed partly from a reduction in military spending at the end of the Cold War, which limited the development of completely new aircraft designs. It became more cost-effective to add new, improved features to existing platforms. Later variants of 4th gen aircraft progressively enhanced their characteristic technologies and incorporated some emerging fifth-generation technologies, such as high-capacity digital communications, leading to classification as an intermediate generation (4.5, 4+, or 4++). Thus, 4.5 generation aircraft are fundamentally fourth-generation fighters but with enhanced capabilities provided by technologies closer to those seen in fifth-generation fighters. Many of these types remain in frontline service today. These aircraft feature advanced digital avionics based on microchip technology and highly integrated systems. They are adapted to operate in high-tech warfare where both advanced avionics and super maneuverability are key to success. Features can include reduced radar cross-section (sometimes referred to as basic stealth), radar absorbent materials, thrust vector controlled engines, greater weapons carriage capacity, and extended range and endurance. The addition of an Active Electronically Scanned Array (AESA) radar is often considered a significant game-changing combat capability defining this sub-generation. AESA radar allows fighter aircraft to perform limited Airborne Early Warning and Control functions. Advances in computer technology and data links also allowed 4.5 generation fighters to be integrated into a network-centric battlespace, where fighter aircraft have much greater scope to conduct multi-role missions. Examples of twin engine fighter aircraft can be found in this generation and others.
According to available open sources, fighters in this generation could include:
- Mikoyan MiG-35
- Sukhoi Su-30MKI/M/MK/SM
- Sukhoi Su-34 Fullback
- Sukhoi Su-35S Flanker-E
- Chengdu J-10B/C
- Shenyang J-11B/D
- Shenyang J-15
- Shenyang FC-31/J-31 (early version might be considered 4.5)
- Dassault Rafale
- Eurofighter Typhoon
- Saab JAS 39 Gripen (later variants)
- Boeing F-15SE Silent Eagle
- Boeing F/A-18E/F Super Hornet
- HAL Tejas (Mk 1A and beyond)
Fifth Generation Jet Fighters (2005 to date)
A fifth generation fighter is a jet fighter aircraft incorporating major technologies developed during the first part of the 21st century. As of today, these are the most advanced fighters in operational service. A quantum improvement in the fighter’s lethality and survivability has been a key requirement for achieving generational change. While characteristics are not universally agreed upon, the technologies that best epitomize fifth-generation fighters are advanced integrated avionics systems that provide the pilot with a comprehensive picture of the battlespace and the extensive use of low observable “stealth” techniques. 5th Generation aircraft typically include significant stealth features, low-probability-of-intercept radar (LPIR), agile airframes with potential for supercruise performance (sustained supersonic flight without afterburners), advanced avionics features, and highly integrated computer systems capable of networking with other elements within the battlespace for enhanced situational awareness and C3 (command, control, and communications) capabilities. Improved situational awareness is achieved through multi-spectral sensors located across the airframe, allowing the pilot to have a near 360-degree view without extensive maneuvering. These aircraft are also ‘born’ networked, designed to receive, share, and store information to enhance the overall battlespace picture. Fifth-generation fighter capabilities are largely defined by their software, and ongoing software development is crucial for maintaining their edge against evolving threats. These aircraft aim to allow the pilot to maintain decision superiority over an adversary, increasing survivability and contributing to battlespace dominance when combined with effective lethality. The j 20 fighter aircraft is considered by some to be a fifth-generation type.
According to available open sources, fighters in this generation could include:
- Lockheed Martin F-22 Raptor
- Lockheed Martin F-35 Lightning II
- Sukhoi Su-57 (Formerly T-50 PAK FA)
- Chengdu J-20 (Claimed capability)
Sixth Generation Fighter Aircraft
With the fifth generation slowly entering service, attention is already turning towards potential requirements for a sixth generation. The exact needs for such a fighter are still under debate and in the conceptual design phase. The fifth-generation abilities for battlefield survivability, air superiority, and ground support will likely need to be significantly enhanced and adapted to future threat environments. Development time and cost are expected to be major factors in defining practical roadmaps for 6th generation aircraft. Potential features could include hypersonic speed, advanced dual-mode engines, adaptive airframe shapes, and even integration with or command of unmanned systems. At this stage, it is not clear to what extent drones and other remote unmanned technologies will participate, either as loyal wingmen aircraft controlled by a sixth-generation command fighter or potentially even replacing the pilot in autonomous or semi-autonomous command roles. Studies such as the US F/A-XX program and UK-led BAE Systems Tempest are ongoing projects exploring these concepts. Unmanned combat aircraft system projects are also progressing globally, including the joint French-Swedish nEUROn, the UK’s BAE Taranis, Northrop Grumman’s X-47B, and follow-on US Navy programs. Similar unmanned combat aircraft projects are also underway in Russia and China.
In conclusion, the classification of fighter aircraft into generations provides a useful, albeit unofficial and broad, framework for understanding the significant technological leaps that have defined the evolution of aerial combat. From the early subsonic jets of the first generation to the stealthy, networked platforms of the fifth, and the conceptual designs of the sixth, each era represents a distinct advancement in speed, power, avionics, and combat capability. This ongoing progression continues to push the boundaries of aerospace engineering and military strategy.
References:-
- https://www.airforce-technology.com/features/top-sixth-generation-fighter-jets/
- https://www.sldinfo.com/wp-content/uploads/2014/05/Air-Combat-Seminar-summary-AndrewMcL.pdf
- https://www.fighterworld.com.au/az-of-fighter-aircraft/five-generations-of-jets
- http://www.codeonemagazine.com/archives/2005/articles/oct_05/
- https://en.wikipedia.org/wiki/Fifth_generation_fighter
- https://www.airforce-technology.com/features/top-sixth-generation-fighter-jets/?utm_source=Army%20Technology&utm_medium=website&utm_campaign=Must%20Read&utm_content=Image
- https://migflug.com/jetflights/fighter-jet-generations/
- http://www.aerospaceweb.org/question/history/q0182.shtml
