India greenlights 5th-gen stealth fighter jet project: Classification of fighter jets into generations and their significance explained

A model of Advanced Medium Combat Aircraft (AMCA) on display at the Aero India 2025. (File/PTI)

In a significant development that moves India closer to building its first fifth-generation stealth fighter, the Union Ministry of Defence on Tuesday approved the execution model for the Advanced Medium Combat Aircraft (AMCA) programme. The development marks a critical step towards realising India's ambition of joining the elite club of nations capable of designing and producing next-gen combat aircraft.

Defence Minister Rajnath Singh on Tuesday approved the execution framework for AMCA which will see the Aeronautical Development Agency (ADA) lead the project in partnership with the industry. "This is an important step towards harnessing the indigenous expertise, capability and capacity to develop the AMCA prototype, which will be a major milestone towards Aatmanirbharta in the aerospace sector," the Defence Ministry said.

The Advanced Medium Combat Aircraft is a fifth-generation, stealth, multi-role fighter jet being developed in India for the Indian Air Force and Navy.

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Where India stands
As one of the most threatened nations with two nuclear-armed neighbours as adversaries, India faces a mounting challenge to meet its evolving needs. The Indian Air Force currently operates a fleet of 31 squadrons of fighter aircraft, against a minimal requirement of 42. This shortfall is due to the retirement of older aircraft like the MiG-21, MiG-23, and MiG-27, which were phased out in the 2000s and 2010s without sufficient replacements.

On the other hand, China has already unveiled two sixth-generation fighter jets - the Chengdu J-36 and Shenyang J-50. The nation also plans to increase production of its J-20 aircraft to 100 a year and targets to have 1,000 by 2030, when AMCA will be making its first flight. It will have 1500 by 2035, when India will optimistically induct the AMCA. Pakistan is already in talks with China to induct the J-35A with China reportedly fast-tracking deliveries of the stealth fighters to Pakistan. Also, around 200 Pakistani technicians and engineers are working with TAI on the Turkish 5th-generation aircraft.

How are fighter jets classified?

Simply put, fighter jets are categorized into different generations based on their features, capabilities, performance and year of development. In the absence of a clearly defined features or capabilities to demarcate one generation from the other, the categorization remains a broad-based concept with authorities identifying different technology jumps as key, dividing fighter development into different numbers of generations.

In 2004, Aerospaceweb listed the basic classification into five generations which has since been widely accepted. Five generations are now widely recognised, with the development of a sixth underway. The 4th generation has also been sub-categorized into 4 and 4.5.

Also Read: Rajnath Singh approves building of 5th generation fighter plane programme to boost private and public sectors

What are sixth generation aircraft?

The sixth generation technologies include advanced digital capabilities, high-capacity networking, Artificial Intelligence, data fusion, cyber warfare, and battlefield command, control, and communications capabilities. Its features include increased speed and range along with advanced stealth airframes and avionics. It also has a more modular design, with primary aircraft components able to be swapped within hours to optimize depending on mission requirements and ease the introduction of future upgrades.

The countries that have it:

On September 14, 2020, the USA revealed that it had secretly designed, built, and flown at least one prototype of its Next Generation Air Dominance (NGAD) fighter. On March 21, 2025, President Trump announced that the aircraft would be the F-47 and that Boeing would be awarded the engineering and manufacturing development contract, worth more than USD 20 billion.

In December 2023, the UK, Japan and Italy merged their previously separate sixth-generation projects to jointly develop a sixth-generation stealth fighter as part of the Global Combat Air Programme. The aircraft is expected to enter service in 2035.

On December 26, 2024, China unveiled two sixth-generation fighter jets - the Chengdu J-36 and Shenyang J-50, representing their next evolutionary leap based on two decades of R&D.

Fifth Generation fighter jets (2005 till date)

A fifth generation aircraft is a fighter jet developed with major technological improvements developed during the early 21st century. These aircraft are largely defined by their software and allowing a pilot a complete view of the battle space while using advanced stealth techniques.

Technologies that set the fifth generation fighters apart from its predecessors include stealth, low-probability-of-intercept radar (LPIR), agile airframes with super cruise performance, advanced avionics features, and highly integrated computer systems capable of networking with other elements within the battle space for situation awareness that includes providing the pilot with a 360-degree view of the battlefield without having to maneuver the aircraft. Fifth generation fighter jets essentially facilitate greater chances of survivability and dominance.

Fifth generation fighter jets include the Lockheed Martin F-22 Raptor and Lockheed Martin F-35 (USA), Sukhoi T-50 PAK FA/Sukhoi Su-57 (Russia) and Chengdu J-20 (China).

Four and a half (4.5) generation fighter jets (late 1980s to 1990s)

Simply put, 4.5 generation aircraft are fourth generation fighters with combine basic characteristics of fourth generation planes with more advanced technologies that provide them enhanced capabilities that may appear to mimic fifth generation fighter jets. These aircraft have advanced digital avionics and highly integrated systems which allow them greater maneuverability to succeed in high-tech warfare. Some of their features include stealth, radar absorbent materials, thrust vector controlled engines, greater weapons carriage capacity and extended range and endurance.

The concept of having a half incremented generation originated during the end of the Cold War era with forced reductions in military spending that made adding new features and improvements to existing platforms more cost-effective. It was when the later variants of the fourth generation jets incorporated significantly enhanced technologies, including those in fifth-generation aircraft, that they were categorized separately as 4.5 generation fighters.

Fighter jets included in the 4.5 generation include the Boeing F-18E/F Super Hornet, Sukhoi Su-30, Sukhoi Su-33, Sukhoi Su-35, Eurofighter Typhoon, Saab Gripen, Tejas Mk1A and the Dassault Rafale.

Fourth generation fighter jets (1970-1980s)

Having debuted in the mid-1970s, this generation of fighter jets are still used by airforces in several countries across the world. These jets are mostly multirole aircraft capable of switching between air-to-air and air-to-ground missions, thus blurring the line between air defence and ground attack missions.

The use of composite materials in fourth generation fighter jets revolutionized their stealth capabilities. Better flight control systems, targeting sensors, laser and GPS-guided precision weapons, active air-to-air missiles, and improved electronic warfare systems set them apart from the predecessors.

Third Generation Fighter Jets (1960s to 1970)

This generation of jet fighters were designed to be multirole fighters capable of carrying out air defence as well as ground attack missions. The major change that this generation of fighters brought was that it was no longer necessary to visually acquire opponents to neutralize them.

These jets were capable of carrying a wide range of weapons and ordnance such as air-to-ground missiles and laser-guided bombs. They were also capable of engaging in air-to-air interception beyond visual range. They were capable of sustained supersonic speeds, carried improved fire control radars and semi-active air-to-air missiles along with the first generation of tactical electronic warfare systems.

Second generation fighter jets (1950s to 1960s)

This generation of fighter jets featured sustained transonic and supersonic dash capabilities. It had a basic fire control radar and used guided air-to-air missiles. Advancements in engine designs were also incorporated in this generation to enable them to sustain supersonic speeds.

This generation saw the introduction of technologies such as air-to-air radar, infrared and semi-active guided missiles and radar warning receivers. This generation also facilitated the extension of engagement ranges as well as higher accuracy. They were later sub-categorized as Interceptors and Fighter-Bombers depending upon their roles.

First generation fighter jets (1940s-1950s)

This category comprised the earliest subsonic fighter jets that appeared during and after World War II. While they were similar to their piston-engine counterparts in most aspects, what set them apart was their advance in speed over their predecessors. These jet engines, which operated in the subsonic regime faced controllability issues at transonic speeds. Also, they did not have any radars or self-protection countermeasures and were armed with machine guns or cannons and unguided bombs and rockets.