Is likely to be the only peer level competitor to the United States over the next fifty years. While a conflict is unlikely—a Third World War is in nobody’s interests—the United States must be prepared for such an eventuality.
As with all modern conventional wars, airpower and air superiority will play a key role. For the United States, the stealthy Lockheed Martin F-22 Raptor will be America’s premier weapon to ensure dominance over the skies until it is eventually replaced by whatever comes out of the U.S. Air Force’s F-X program.
The most direct Chinese analogue to the Raptor is the Chengdu J-20. How would such a jet fair against America’s best?
Not much is known about the Chinese jet—it might not even be a fighter in the traditional sense of the word. It could be a specialized aircraft that is specifically designed to attack the sinews of U.S. power projection capabilities in the Western Pacific as part of an overall Chinese anti-access/area denial strategy (A2/AD) . Basically, the jet might be optimized to hit support assets like tankers, AWACS, JSTARS or even carry long-range cruise missiles to attack scattered U.S. bases and aircraft carriers in the region.
(This first appeared in 2015.)
There are some indications that the J-20 is a primarily a strike aircraft but with a robust air-to-air capability. Like the American F-35, the newest J-20 prototypes appear to have an electro-optical targeting system mounted under the nose. That sensor could be Beijing A-Star Science and Technology’s EOTS-89  electro-optical targeting system (EOTS). A dedicated air superiority fighter wouldn’t need that kind of sensor.
There are also indications that the Chinese jet carries an active electronically scanned array radar  (AESA). Allegedly, the J-20 would be fitted with a Type 1475 radar, which is supposedly being tested on a China Test Flight Establishment owned Tupolev Tu-204. However, there is no way to confirm that information because the People’s Liberation Army Air Force (PLAAF) isn’t really all that forthcoming about sharing information about its developmental projects. That being said, given Beijing’s interest in the Su-35—which is mostly likely driven by a desire to harvest that Flanker variant’s radar and engine technology , I have my doubts about how far along the Chinese have gotten on developing an operational AESA.
Perhaps the most compelling evidence that would point to the J-20 being optimized for the strike role is the fact that the airframe is enormous but has relatively small wings. It’s also seems to have huge weapons bays. While such a configuration works well for a fast supersonic strike aircraft, it’s not ideal for an air superiority fighter that needs be able to sustain high rates of turn.
Moreover, China hasn’t demonstrated that it has the requisite engine technology necessary to power an air superiority fighter of that size. The People’s Republic hasn’t perfected its indigenous WS-10, let alone come close to finishing development of the next-generation WS-15. In fact, China hasn’t demonstrated it can build any reliable jet engine—and that’s including designs that it stole from Russia. But a strike aircraft doesn’t need to have a spectacular thrust to weight ratio—thus the jet’s current twin Russian-built Saturn AL-31F engines might be adequate for China’s purposes.
Further, there is a strong argument to be made that short-range tactical fighters like the F-22 and F-35 are ill-suited for operations in the Western Pacific  where distances are vast and bases are scarce. The same geographic constraints also apply to the Chinese. That means that jets like the F-22 and F-35 need tankers to operate over those vast distances. The most logical way for the Chinese to tackle American and allied airpower is not to confront those forces head-on but rather by removing their ability to fight. That means going after U.S. bases, tankers and communications nodes. Thus in that sense, the J-20 could be China’s means to establish air superiority if viewed through that lens. In that sense it might have the upper hand against the F-22.
Of course, this is all conjecture. Only the PLAAF knows where the J-20 fits into their order of battle, but it could prove to be a formidable foe.