US commanders say 5th-gen fighters will be 'critical' in a war. Here's how F-35s and F-22s stack up to Russia's and China's best jets.

• The US's newest fifth-generation fighter, the F-35, is again under fire from Congress.
• Despite lawmakers' displeasure with it, US military commanders say the jet is indispensable.
• The commanders all see Russia's and China's fifth-generation fighters as major concerns.

The F-35's cost and procurement issues have once again put the advanced fighter jet in Congress' sights.

At a House Armed Services Committee hearing in April, Reps. John Garamendi and Donald Norcross - chairmen of the tactical air and land forces and readiness subcommittees, respectively - made clear their frustration with the program and told the military not to expect additional money for it.

Top US commanders, however, insist that the F-35 and the F-22 - the US's two fifth-generation jets - are indispensable.

In March, Adm. Philip S. Davidson, then head of US Indo-Pacific Command, told the Senate Armed Services Committee that fifth-generation fighters "are the backbone of any of our planning for a crisis forward in the theater" and called them "critical to any future war-fight we might have."

Two days later, Adm. John C. Aquilino, Davidson's successor, told the committee that he "would be concerned if we lessened our capacity of fifth-generation airplanes. I think they are needed to win."

At separate Senate and House Armed Services Committee hearings in April, Gen. Tod Wolters, head of US European Command and the Supreme Allied Commander Europe, said the F-35 was needed "to ensure that we have the competitive advantage" and that the US and its allies would be "weakened" if its production was reduced.

The officials all cited the development of Russian and Chinese fifth-generation jets as a major concern.

The Raptor and the Lightning

Introduced in 2005 and 2016, respectively, the F-22 Raptor and the F-35 Lightning II were intended to usher in a new era in which stealth technology played a dominant role in the Air Force's fighter inventory.

"The F-35 and the F-22 are fundamentally related. They are cousins," Douglas Birkey, the executive director of the Mitchell Institute for Aerospace Power Studies, told Insider.

The jets were to work in tandem, with the F-22 as the air-to-air dominance platform and the F-35 excelling at ground-strike missions, though it was also capable of air-to-air combat.

The F-22 can carry eight air-to-air missiles or two 1,000-pound bombs and two air-to-air missiles in its internal weapons bays.

The F-35 can carry 18,000 pounds of missiles and bombs internally and on external hardpoints. For close combat, the F-22 has a 20 mm rotary cannon and the F-35 a 25 mm rotary cannon.

F-22s have flown deterrence and strike missions in Syria, while Air Force and Marine Corps F-35s have struck targets in Iraq and Afghanistan.

But their electronics suites and stealth coatings are just as important as their armaments, especially for the F-35.

While the F-22 is better at dogfighting, the F-35 has far more advanced electronics. "Its ability to understand the battlespace is like none other. It is literally covered in sensors," Birkey said of the F-35.

That gives F-35 pilots a massive advantage, particularly with the jet's ability to integrate data from other F-35s and friendly aircraft instantly, allowing them to see much more of the battlefield. The Army and the Air Force have already practiced using the F-35's sensors to guide long-range artillery fire.

Despite delays and cost overruns, senior US military officials say the F-35 is extremely valuable and that the other countries fielding it feel the same.

The Mighty Dragon

The first non-US fifth-generation fighter to enter service was China's Chengdu J-20, also known as the Mighty Dragon. Introduced in 2017, it was developed in response to the F-22 and the F-35.

China's stealth program is believed to be based on plans stolen from the US. The J-20 looks similar to the F-22 and plays a similar air-dominance and interceptor role for the Peoples Liberation Army Air Force (PLAAF).

It doesn't have a cannon, but the J-20 does have internal weapons bays, which can hold six air-to-air missiles.

The J-20 is currently believed to be inferior to its American counterparts in a straight-up dogfight, in part because the Chinese have struggled to build efficient engines.

Early models were underpowered and lack thrust-vectoring, which allows the pilot to control the direction of the engine thrust.

The Chinese initially used Russian-made engines but are now fitting J-20s with domestically produced engines: the WS-10C is currently being installed as a stopgap until the WS-15 arrives.

The WS-15 will put the J-20 "on par" with the F-22 and be available within two years, Chinese military sources told The South China Morning Post in April.

But China has three distinct advantages going forward.

Most of the likely combat scenarios it faces are close to its territory, lowering deployment and upkeep costs for China compared to those for US fifth-generation jets that have to deploy and operate from forward bases or ships.

The J-20 is also still in production, meaning it can be further refined and enhanced, while the F-35 program now faces budget limits and F-22 production has ceased entirely.

China's air-to-air missile arsenal is also considerably advanced.

The Felon

The Su-57, known to NATO as the Felon, is Russia's entry in the fifth-generation contest.

It was officially introduced into service in December, but it first flew in 2010 and has been in development since 2002.

Four internal weapon bays can carry six air-to-air missiles, and six more can be attached to external hardpoints on the wings. It also has a single-barreled 30 mm autocannon for close combat.

Not much is known about the Su-57. Its size, shape, and maximum speed of about Mach 2 (similar to the J-20 and F-22) suggest it's meant to play an air-dominance role like the F-22.

Russia has a history of producing advanced electronic-warfare technology, but some analysts are skeptical of the Su-57's stealth capabilities in comparison to its American and Chinese counterparts.

Two Su-57s have deployed to Syria twice, but only for brief periods and without conducting combat missions.

"They didn't really send it there in volume or for sustained periods, so that would suggest that some of the issues that would be in development are probably still in development," Birkey said.

But Russia has grand plans for the Su-57.

It hopes to acquire 76 of them by the end of 2028, using them to test hypersonic missiles and, starting in 2024, to operate S-70 Okhotnik-B armed drones alongside them.

The drone will be a "loyal wingman" controlled by Su-57 pilots.

Stealth is the future

While the fifth-generation race is today dominated by the US, China, and Russia, multiple countries intend to build their own fifth- and sixth-generation fighters.

South Korea recently unveiled a stealth fighter (though less stealthy than the F-35) that it is developing with Indonesia and hopes to field by 2028.

India, Turkey, and Britain each hope to field their own fifth- or sixth-generation jets between 2028 and 2035, while Japan intends to field a sixth-generation stealth fighter by 2035. France, Germany, and Spain are also working together on a sixth-generation fighter they hope to have operational by 2040.

"The fact that it's proliferating out this widely shows you that to be relevant in the modern combat environment, you're either fifth-generation or you're an expensive target," Birkey said.

The US Air Force is working on its own sixth-generation fighter, known as the Next Generation Air Dominance (NGAD) program.

An NGAD demonstrator has already been flown, but Gen. Mark D. Kelly, head of Air Combat Command, expressed concern the US might not be able to "field this capability before someone like the Chinese fields it and uses it against us."

Kelly's comments reflect the complexity expected in future conflicts and the importance of stealth aircraft to overcoming it.

"The wars that we're increasingly looking at, and for which the F-22 and F-35 are built, are wars where if we do not succeed, life fundamentally changes in a very bad way," Birkey said. "We need to wake up to that and act accordingly."