Experts who are close to the subject of aerial warfare have stated that China’s latest stealth fighter, the J-31, and J-20 fighter jet are variants that were inspired by F-35. This could mean that the Chinese took intricate details from the fighter jet and implemented them on their own fighter jets. According to AVIC Chairman, Lin Zuomin, he had this to say about J-31 if it ever met F-35 in an open air fight:Story here.
“The J-31 will finish it off in the sky.”
According to the Snowden files, there are several details that outline the scope of Chinese F-35 espionage efforts. These ranged from acquiring the radar design of the fighter jet, as well as detailed engine schematics. These schematics would most likely enable the Chinese to build a fighter whose speed matched that of F-35 and they could also replicate the cooling system of the engine, to prevent it from overheating even when it was stressed to its limits.
The leaked documents from Snowden also reveal that several terabytes of data related to F-35 joint strike fighter program were stolen, meaning that if the Chinese were actually responsible for the hack, they had sufficient information on their hands to build a fighter jet of their own in order to match the prowess of F-35.