Innovation in the skies: Tracking the rise of 6th generation fighter jets

The first mass-produced 5th-generation fighter jet is considered to be the F-22 Raptor. Its prototype took to the skies in 1990, and the aircraft was so innovative, uncompromising, and expensive that to this day—over 30 years later—no one in the world has managed to build anything that matches the Raptor in terms of aerial combat capability.

Despite the passage of time, it still doesn’t have much competition—the United States, followed by a group of allies, operates F-35 Lightning II jets (built on different principles), China has the air superiority fighter J-20, which, despite the years, still struggles with its intended engine, and Russia has no more than 20 Su-57s, whose stealth features are questioned by experts.

Meanwhile, the Pentagon has already begun phasing out the oldest F-22 models, transitioning to air superiority F-15EX aircraft as a bridge solution, classified as generation 4.5. The Raptor's ultimate successor is an entirely new aircraft developed under the NGAD program. Its creators claim it will belong to the next sixth generation.

Originally, the generation classification referred to jet fighters designed for air combat. Over time, however, due to advancements in technology, which turned former fighters into multirole aircraft, the generation classification began to apply to combat aircraft in general. Some manufacturers even use it for bombers like the B-21.

What are the generations of combat aircraft, and what features do these classified machines have?          

• Generation 1 – early, pioneering jets built directly after World War II with many features common to piston-engine aircraft.
• Generation 2 – aircraft that primarily used air-to-air missiles instead of machine guns and cannons.
• Generation 3 – machines adapted for very high speeds, achieved partly through variable-geometry wings.
• Generation 4 – multirole aircraft with high manoeuvrability and fly-by-wire control (without mechanical connections between the cockpit and control surfaces).
• Generation 4.5 – aircraft with aerodynamics from Generation 4 but much more modern avionics. Although they physically resemble their predecessors from the '70s and '80s, they have significantly enhanced capabilities.
• Generation 5 – aircraft combining multirole capabilities, high manoeuvrability, supercruise (supersonic speed without afterburners), and stealth (low observability) features.
• Generation 6 – futuristic machines with unspecified characteristics, surpassing the capabilities of the previous generation; advanced electronic combat abilities, beyond-visual-range combat, and ground attack capabilities. Potential features include AI pilot support, optional unmanned operation, and the use of energy weapons like lasers.

Who is building 6th generation fighter jets?

The United States has been conducting the NGAD program since 2014. This program aims to develop not only a specific aircraft but a "family of systems" to replace the retiring Raptors.

Thanks to AI, this family is expected to include a manned aircraft and "loyal wingmen"—drones capable of performing some of the riskiest tasks and protecting the manned aircraft.

The U.S. Navy is also developing its own next-generation aircraft under the F/A-XX program, which requires planes with different characteristics (including long-range and designs suited to catapult-assisted takeoffs). These futuristic aircraft are intended to replace Super Hornets on aircraft carriers and complement the F-35C.

Russia is also working on a successor to its heavy air superiority fighter, the MiG-31. According to Kremlin propaganda, the Mikoyan plants are close to completing a prototype known as PAK DP (though the widely used MiG-41 name is unofficial).

This is supposed to be a very high-speed aircraft—up to Mach 5 (6100 km/h)—capable of reaching an altitude of 40 km, striking targets both in the atmosphere and in space, carrying hypersonic weapons and countering them as well. This is possible due to a novel pulse detonation engine (PDE).

At the current stage, assessing how close these claims are to reality is difficult. The war in Ukraine has already debunked many other Russian "super weapons," so these claims regarding the new aircraft should be taken with a healthy dose of skepticism.

European countries aim to build next-generation aircraft through international cooperation. Two competing programs are currently underway. GCAP (Global Combat Air Programme) is an initiative by the United Kingdom, Italy, and Japan, building on earlier British projects like the Tempest aircraft and Japan's technology demonstrator, the Mitsubishi X-2.

The second European program, FCAS (Future Combat Air System), is led by France, Germany, and Spain. Its goal is to develop both new manned combat aircraft and supporting drones.

After exiting the GCAP program, Sweden is also independently developing a next-generation aircraft. The FFS program aims to find a successor to the Gripen. Working in collaboration with Brazil on the JAS 39E/F Gripen, classified as a 4.5-generation aircraft, Sweden hopes to make a generational leap and replace the current fleet with a 6th-generation aircraft.

Brazil, China, and India are also conducting their own development programs. Brazil aims to create a futuristic aircraft through Embraer's efforts, leveraging experiences from its collaboration with Sweden, which resulted in the JAS 39E/F Gripen.

India, which is currently developing its 5th generation aircraft, the HAL AMCA, also plans to work on its successor. According to very general plans, the new aircraft will be optionally manned, cooperate with loyal wingmen and swarms of drones, and utilize energy weapons.

China is currently developing its fifth-generation aircraft, the large Chengdu J-20 air superiority fighter. Work on its successor is also underway, as displayed in concept graphics released by AVIC. Its characteristics and technical data have not yet been disclosed.