North Korean hackers reportedly infiltrated a computer network belonging to a South Korean aerospace firm’s computer network and made off with blueprints for the F-15 Eagle—the American-designed jet fighter that forms the backbone of the U.S. and South Korean air forces.

But don’t panic quite yet. There’s not much Pyongyang’s engineers can actually do with the blueprints. For sure, we won’t be seeing F-15s rolling out of some North Korean factory in the distinctive dark camouflage of the Korean People’s Air Force.

The hack began in 2014 and South Korean authorities first detected it in February this year, South Korea’s police cyber investigation unit told Reuters. In the meantime, the hackers gained access to the networks of two defense-industry conglomerates in South Korea and made off with some 42,000 documents.

Among the documents were blueprints for the wing design of the twin-engine, supersonic F-15, police told Reuters. Korea Aerospace Industries builds the Eagle’s wings under contract with Boeing, the No. 2 U.S. defense firm. Boeing has described KAI as a “valued supplier” (PDF).

The U.S. Air Force operates hundreds of F-15s. Undefeated in air combat since its debut in the early 1970s, the Eagle is still America’s main air-to-air fighter. South Korea acquired 61 F-15s starting in 2005.

Although the F-15’s basic design is, by now, more than 50 years old, the Eagle is still leaps and bounds more sophisticated than any warplane North Korea’s tiny, impoverished air force possesses.

While Pyongyang manages to produce its own firearms, artillery, armored vehicles, and warships, it’s never quite mastered the delicate art of designing and manufacturing military aircraft. The Korean People’s Air Force operates hundreds of jet fighters, but most of them are single-engine MiG-21s that North Korea bought from the Soviet Union in the 1960s, ’70s, and ’80s and has maintained ever since.

While supersonic and highly maneuverable under certain circumstances, the MiG-21 is badly outclassed by more modern jets such as the F-15. In theory, Pyongyang would welcome a new fighter plane—and desperately seek the blueprints to build it.

But in practice, North Korea has neither the know-how nor the resources to copy the F-15 or even adapt the Eagle’s blueprints to its own design. “North Korea will never build a serious air force,” Dr. Robert Edwin Kelly, an associate professor at Pusan National University in South Korea, told The Daily Beast via email.

History bears this out. In the 1980s, North Korea established a fighter-jet factory—the Seventh Machine Industry Bureau in Panghyon—and even bought, from the Soviets, components for twin-engine MiG-29s that were, at the time, on the cutting edge of warplane technology.

But the Seventh Machine Industry Bureau only managed to assemble three MiG-29s. “The plan proved too ambitious for North Korea,” explained Stijn Mitzer and Joost Oliemans, independent military experts who write together at Oryx Blog.

Of course, it’s possible that North Korea could pass along the F-15 blueprints to a country that could make use of them. “The only option would be to try and sell the information, for which only China could be seen as a reasonable candidate,” Oliemans told The Daily Beast in an email.

Beijing’s own hackers have been implicated in the thefts of several U.S. weapons designs, including the F-22 and F-35 stealth fighters, the more modern successors to the F-15.

The F-35 hack was apparently the most damaging to the United States. In 2007, Chinese cyberspies reportedly hacked broke into servers belonging to U.S. aerospace firm Lockheed Martin and made off with design information on the F-35. Just a few years later, a Chinese firm unveiled a stealth fighter prototype, the J-31, that some observers suspect is at least partly based on the stolen F-35 data.

But Oliemans said he doubts the F-15’s wing would be of much interest to the Chinese. “If the hack only compromised the wing design, which isn’t exactly the most modern piece of data you’d want to acquire about the F-15, I wouldn’t suspect China to be interested at all.”

“In fact,” Oliemans continued, “given the amount of blueprints and other data China is reported to have hacked themselves of aircraft such as the F-35 and F-22, I wouldn’t be surprised if they already had access to the F-15’s wing design already.”

All that is to say—don’t worry about the wing blueprints. China probably wouldn’t want to copy the F-15, and North Korea probably can’t. But that doesn’t mean the alleged North Korean cybertheft isn’t alarming, in principle. Oliemans called it a “worrying development.”

Kelly seconded that notion. “They’ll try and try until they get through,” he said of the North Korean hackers. “Norms won’t restrain them, nor do they have an economics relationship with the U.S. or South Korea that would be jeopardized by this.”

The next time Pyongyang’s cyberspies attack, they might get something more useful than a 50-year-old wing design.