Washington is “not too far away” from a production line for its F-47 sixth-generation fighter, a senior US Air Force official has said, as China presses ahead with flight-testing two different next-generation combat aircraft of its own.

During a virtual event hosted by the Mitchell Institute for Aerospace Studies on Monday, Brigadier General Timothy Helfrich, the service’s portfolio acquisition executive for fighters and advanced aircraft, said the F-47 would be “the world’s first sixth-generation fighter”.

He said the aircraft was on track to fly before US President Donald Trump’s term ended in January 2029. Its first flight is targeted for 2028.

Meanwhile, China’s two tailless next-generation fighters, commonly known as the J-36 and J-50, have been observed on test flights since December 2024.

The secrecy surrounding the programmes makes direct comparisons difficult. US officials have said the F-47 builds on years of classified demonstrator testing, while Beijing has offered few details about either Chinese aircraft beyond brief footage released by Chinese state media in June.

A day after Helfrich’s comments, the US Navy selected Boeing – already developing the F-47 – for its F/A-XX carrier-based fighter under a development contract worth more than US$20 billion, putting both US sixth-generation fighter programmes under the same roof.

The award adds weight to Helfrich’s description of fighter production capacity as a “strategic asset”. He noted that the US had only three active fighter lines – for the F-35, F-15EX and F-16.

Andreas Rupprecht, an aviation analyst and expert on the Chinese air force, cautioned that Helfrich’s comments might not mean “serial production” was imminent, noting that the first F-47 development aircraft was still some way from completion.

The US Air Force plans to acquire at least 185 F-47s, which are expected to have a combat radius of more than 1,000 nautical miles (1,850km). Helfrich said the fighter would be “much more survivable” than existing fifth-generation aircraft.

Rupprecht said the J-36 – built by Chengdu Aircraft Industry Corporation (CAIC) – currently had “no true US Air Force counterpart”, while the smaller Shenyang aircraft commonly referred to as the J-50 was the closer comparison with the F-47 in size and configuration.

Brendan Mulvaney, director of the US Air Force’s China Aerospace Studies Institute, broadly agreed that the J-50 looked closer to the F-47 in size and appearance, but cautioned against “mirror imaging”. Similar shapes could partly reflect the requirements of low-observable aircraft, he noted, while their technologies, weapons and roles could still differ. The J-36 is a large, three-engined tailless aircraft with a side-by-side cockpit.

The South China Morning Post reported earlier on what appeared to be a possible fifth prototype, suggesting CAIC was continuing to refine the design through successive prototypes as flight-testing progressed. More recent footage has complicated efforts to determine how many are flying. Rupprecht said the number 36011 had appeared on three apparently different aircraft. He said it was unlikely that they represented a single aircraft repeatedly modified, given changes to the intakes, engines, exhausts and, most significantly, the landing gear. Clues about the J-50 have also surfaced.

Research published in August by the Shenyang Aircraft Design and Research Institute pointed to future fighters using greater autonomy, satellite-independent navigation and reconfigurable formations of uncrewed aircraft.

The paper did not name the J-50 or confirm that it would have those features, but the emphasis on autonomy and networking has parallels with the US approach: the F-47 is intended to operate alongside collaborative combat aircraft. “Especially in these highly contested environments, no one’s going to be fighting alone,” Helfrich said.

Timothy Heath, founder of defence consultancy Perceptum, said the two militaries appeared to be exploring similar ideas but were still experimenting with how best to combine crewed and uncrewed systems.

“It may take some time before we have clarity on their exact visions,” he added.

Rupprecht described the visible changes to the J-36 and J-50 as “technical and aerodynamic refinements”, saying the programmes appeared to be progressing from a “rather rudimentarily equipped prototype” towards later aircraft showing “signs of integrated systems”.

The latest prototypes appeared to be moving towards aircraft equipped with radar, “more comprehensive avionics” and potentially newer engines, he said.

Mulvaney was more cautious, describing the changes as “evolution” rather than maturity.

“If it were ‘mature’ then they would stop the changes and move to testing and production,” he said.

“We haven’t seen that yet, so they aren’t ‘ready for prime time’ yet.”

Rupprecht said the next indication of progress would be the appearance of further aircraft, which could suggest a design had been “finalised”. The war in Ukraine has shown the importance of large drone inventories, integration with regular forces and ample stocks of missiles and other weapons, according to Heath.

He added that both the US and Chinese militaries were likely drawing lessons from the conflict on how to use and defend against drones in a high-end war.

Yet which aircraft flew first may be a poor measure of who is further ahead.

Rupprecht cautioned against drawing conclusions from public flight dates, saying “we simply know far too little” about the respective programmes to determine which side was further ahead.

He said it was safe to assume that aircraft developed under the US Next Generation Air Dominance programme had flown before the Chinese designs, but it was unclear how representative those demonstrators were of the eventual F-47.

He added that there could also have been classified precursors to China’s aircraft and that it was unclear whether US and Chinese requirements were comparable enough to conclude that either side had an edge.

“I would simply wait and see on this one.”By Gabriel Dominguez