Why China Leads the U.S. by 10 Years in 6th Gen Fighters?

On December 26, two types of new Chinese stealth fighters were publicly demonstrated in flight. The Economic Times, Fox News, and The Warzone all referred to them as 6th generation or Next-Generation stealth fighters.

Notably, photos taken in Sichuan Province indicate that China’s new aircraft are already marked with serial numbers. According to Chinese military regulations, only equipment that has been formally delivered to combat units is allowed to have serial numbers. This could suggest that China’s 6th generation fighter has already entered mass production and may even be combat-ready.

The New York Post, on the other hand, pointed out that the U.S. military has yet to deploy a 6th generation fighter. This implies that the U.S. Air Force is lagging behind China by as much as a decade. The US Next Generation Air Dominance (NGAD) program, which aims to develop a 6th generation fighter, was proposed back in 2014. However, as of now, there isn’t even a prototype capable of public flight demonstrations.

This has left many Chinese netizens puzzled, given that China’s military budget for 2023 was around $210 billion, while the U.S. military budget is a staggering $916 billion—four times that of China. Why is U.S. military technology falling behind China?

Chinese strategist Professor Wang Xiangsui offers the explanation: the key to developing a new generation of fighter jets lies in having the necessary next-generation research facilities—specifically hypersonic wind tunnels. In this field, the U.S. is at least eight years behind China.

Wind tunnels are research facilities that simulate real-world flight conditions on the ground, with hypersonic wind tunnels reaching speeds of at least Mach 5. Beijing’s JF-22 wind tunnel can simulate speeds up to Mach 30, flight altitudes of 100 kilometres, and continuous operation for more than 100 milliseconds, making it the world’s most advanced wind tunnel. In contrast, the VOA reported in 2023 that the most advanced U.S. wind tunnel, LENS II, can only simulate speeds of Mach 7 and operate for just 30 milliseconds.

JF-22 Supersonic Wind Tunnel (Image source: Xinhua News Agency)

To understand the difference, imagine developing aircraft as training athletes. Having a super-fast treadmill allows engineers to closely observe the athlete’s form and offer precise feedback without having to transport test models to 100 kilometres in altitude. This not only reduces the risk of espionage during development but fundamentally improves the maturity of technology verification machines, ensuring fewer losses and greater safety for test pilots.

While the U.S. Sandia National Laboratory’s Z Machine can accelerate airflow to Mach 30, its primary purpose is to study shock waves for nuclear fusion, and it can only operate for a very brief period. Unlike Beijing’s JF-22, which is designed for continuous operation, the Z Machine cannot simulate sustained high-speed flight conditions needed for aircraft and missiles. It’s like trying to train a sprinter with a treadmill that can only simulate one step. Even if Usain Bolt’s first step is faster than anyone else’s, he won’t win the gold medal if he doesn’t complete the remaining 99 meters.

The U.S. scientific community has been well aware of this 8 years ago. JF-22’s creator, Mr. 姜宗林(Jiang Zonglin), has received the American Institute of Aeronautics and Astronautics Ground Testing Award in 2016 for developing the world’s largest shock wind tunnel, the JF-12. This signals that U.S. academics have clearly recognized the need for U.S. to increase investment in wind tunnel research.

Dr. Jiang Zonglin, Director of the Key Laboratory of High Temperature Gas Dynamics, Chinese Academy of Sciences.

However, as of November 2024, the U.S. remains behind. The most recently delivered wind tunnel at the University of Notre Dame can only reach Mach 10, just one-third of the capability of China’s JF-22.

Notably, the U.S. still boasts formidable scientific potential. In the 2025 QS World University Rankings, 4 of the Top 10 universities are in the U.S., which attracted 280,000 Chinese students went to the U.S. to study. If the U.S. can retain these talented individuals and foster their creativity at NASA, there is still hope for the U.S. to catch up with China in the race for 6th generation aircraft development.

However, the “China Initiative,” launched by Trump in 2018, classified many Chinese scientists working at U.S. universities and research institutions as “economic spies” and “technology thieves.” The Biden administration has not reversed this discriminatory policy. On July 10, 2024, Chinese neuroscientist Professor Jane Ying Wu, accused of having “close ties to Beijing,” lost her lab at Northwestern University, which led to her tragic suicide. As Trump will return to the White House in just 20 days, the fate of Chinese students and researchers in the U.S. remains uncertain.

Prof. Jane Ying Wu

What is clear is this: after World War II, the U.S. demonstrated remarkable inclusivity by welcoming German missile scientists and Japanese bioweapons experts from Unit 731. However, for scientists of Chinese descent, even those students who self-funded their education in the U.S., it seems that America is no longer the platform where they can fully realise their creative potential. According to LinkedIn, in 2023, 80% of Chinese students studying abroad chose to return to China for work.

For a country like the U.S., which relies on high-value-added industries for foreign exchange, losing its inclusivity and judgment on the direction of technological development could not only result in the loss of the 6th generation fighter, but potentially jeopardize its future.

Wernher Magnus Maximilian Freiherr von Braun. Before he served in NASA as the chief architect of the Saturn V super heavy-lift launch vehicle that propelled the Apollo spacecraft to the Moon, he was a member of the Nazi Party and Allgemeine SS, design and co-developed the V-2 rocket during World War II