A downed US jet, a bombed embassy, and 25 years of rumors about how China built its first stealth fighter

• China continues to expand its fleet of J-20 stealth jets and to operate them farther from home.
• The J-20's progress has been accompanied by reports that China stole its tech from the US's F-22.

As China's fleet of J-20 stealth fighters grows, so do suspicions about where Beijing got the technology for it.

"They have profited greatly from their thievery over the years," James Anderson, former acting under secretary of defense for policy, told Fox News in March. "They've put it to good use, and they've come up with an advanced fifth-generation fighter."

Anderson was referring to reports that China obtained secret information about the F-22 and used it to design of the J-20. But the rumors actually go back a quarter-century, to the loss of the first American stealth jet.

On March 24, 1999, NATO began airstrikes against Serbian military targets in response to Serbian atrocities in Kosovo. That NATO would actually intervene and conduct a nearly three-month bombing campaign was remarkable enough. What was shocking was that on March 27, 1999, the Serbs managed to shoot down a US F-117 Nighthawk, the world's first stealth jet.

Though the shape and materials of the F-117 made it difficult to detect with radar, the Serbs were able to analyze NATO flight patterns to estimate the aircraft's route that night.

When the Nighthawk opened its bomb-bay doors, enough of its non-stealth interior surface was revealed for Serbian gunners to guide a Soviet-designed SA-3 missile to the target. Through Serbian resourcefulness and American overconfidence, a 1960s-era missile had destroyed one of the most advanced aircraft in the world.

Though the pilot was rescued, the incident was embarrassing to Washington and a problem for the US military: The wreckage of a top-secret aircraft was strewn over enemy territory. China would have been one of several nations — both friends and rivals of the US — that would have been happy to get a look at the debris.

US-China relations were calmer in 1999 than they had been in the 1950s, but an incident during the bombing campaign caused tensions to spike. On May 7, 1999, US B-2 stealth bombers hit the Chinese embassy in the Serbian capital of Belgrade, killing three Chinese citizens.

Beijing, which had been critical of the NATO bombing campaign, claimed the attack was deliberate, but the US said it was accident caused by faulty intelligence. President Bill Clinton apologized on May 10.

Under the circumstances, there would seem to be little connection between the destruction of an American warplane and the bombing of the Chinese embassy. But in the years since, officials and commentators have drawn a link, suggesting that the Chinese got their hands on the wreckage.

Adm. Davor Domazet-Loso, chief of Croatia's military staff during the NATO bombing campaign, told the Associated Press in 2011 that during the campaign, "our intelligence reports told of Chinese agents crisscrossing the region where the F-117 disintegrated, buying up parts of the plane from local farmers."

"We believe the Chinese used those materials to gain an insight into secret stealth technologies" and "reverse-engineer them," Domazet-Loso said.

Shortly after Domazet-Loso's comments were published, US defense officials said they believed that the Chinese had picked up some of the wreckage but doubted that there was much to be learned much from a plane designed in the 1970s.

At the time, the Global Times, a hawkish tabloid run by the Chinese Communist Party, denied that Beijing had retrieved F-117 debris, but the allegations have resurfaced amid worsening US-China relations.

After a contentious meeting between US and Chinese diplomats in March 2021, reports appeared in Chinese media that described a connection between the downed jet and the embassy bombing.

According to a 2021 story in the Japanese business publication Nikkei Asia, the Chinese articles alleged that the Serbians had given the F-117 wreckage — including stealthy components of the aircraft body and heat-resistant parts from the engine — to China, which stored it in the embassy basement before shipping it home.

The US detected signals from the debris and bombed the embassy but failed to destroy the F-117 wreckage there, the articles claimed.

However badly the Pentagon wanted to guard the F-117's secrets at the time, it would have been reckless, if not lunatic, to commit an act of war against one of the world's most powerful nations.

There is ample evidence that China has made great efforts to steal military and economic secrets — not just from US programs such as the F-22 and F-35 and not just from the US defense industry but also from their Russian partners. (Moscow also said China copied aspects of the J-20 from Russian designs.)

Just as it is natural for nations to spy on each other, it's natural for nations to claim that their opponents are gaining advantages through subterfuge and espionage.

Today, China has perhaps about 150 J-20s in service and Beijing says their operations are expanding. US officials and experts believe Chinese pilots are handling the jet "pretty well" but say that until China develops a better engine it will remain inferior to the F-22.

How much does the J-20 really owe to an American stealth fighter burning in a Balkan field? We may never know.

Michael Peck is a defense writer whose work has appeared in Forbes, Defense News, Foreign Policy magazine, and other publications. He holds a master's in political science. Follow him on Twitter and LinkedIn.