According to the commander of the US Air Force in the Pacific, the US F-35 has at least once encountered a Chinese J-20 fighter in the East China Sea.

“Recently, the F-35s were involved in a close encounter with the Chinese J-20 stealth fighter in the East China Sea.” “I wouldn’t call it a confrontation; we’re impressed with the J-20’s ability to command and control,” said General Kenneth Wilsbach, commander of the United States Pacific Air Forces (PACAF), in an interview on March 15.
General Wilsbach did not specify the exact time and location of the event, nor how many times the two sides have met over the years.
“We see the capability to fly reasonably professionally.” It is too early to tell whether the J-20 series will be a multi-role fighter like the F-35 or a dominant fighter. Air superiority has no air-to-ground capability like the F-22. Really what we’ve seen is air superiority,” he added.

The US official also mentioned the KJ-500 airborne early warning and control aircraft, claiming that it is crucial to China’s long-range strike capability. “KJ-500s support many of their long-range surface-to-air missiles. What really piques my interest is the ability to break that chain of attack “General Wilsbach stated.
The J-20 is a stealth fighter developed by China that is said to be capable of attacking accurately and operating in all weather conditions. The J-20 has been in service with the Chinese army since 2017, but its capabilities are still limited by a series of engine issues.

In January, a Chinese military source said that the J-20 stealth fighter’s WS-10C engine would be upgraded this year, bringing the aircraft closer to the capacity of the F-22 model of America.
The J-20 is powered by a WS-10 engine, which is a temporary solution while Chinese engineers work on the more powerful WS-15 engine, which is reported to be capable of helping this fighter reach its full potential and provide “superior horizontal performance like F-22.” However, the WS-15 development project was also delayed, forcing the manufacturer to replace the Russian AL-31F engine with a derivative of the domestic WS-10 engine. Domestic engines often have problems and are likened to “faulty hearts” on Chinese fighters, forcing the country’s defense industry to find a way to fix it for a long time.
The number of J-20 fighters in service in China has not been disclosed. According to an article in the journal Military Science Technology, roughly 90 J-20s have been delivered, and the Chinese military will require 400-500 of these fighters.
Beijing has lately dispatched J-20 fighter jets to air force units in control of the Taiwan Strait and the East China Sea.