The Americans rolled out their first stealthy aircraft in the 1960s; this was SR-71 Blackbird. There are FIVE documented events to shoot down this aircraft but all failed.
The Americans rolled out and utilized additional stealthy aircraft such as F-117A Nighthawk (low-end) and B-2A Spirit (high-end) in the 1980s which were put to use in several conflicts. Both delivered results, and B-2A surpassed all expectations.
The Americans rolled out F-22A Raptor in the 1990s, and made 5th generation technologies feasible for mass production with the F-35 program. These jet fighters have also served in several conflicts by now.
The Americans are developing B-21 Raider and will finalize it for mass production by 2022. This bomber is 2 decades ahead of B-2A in VLO considerations (the first ELO class).
No country is even close to replicating B-2A design and capabilities in operational capacity - forget B-21.
The Americans have tested a 6th generation prototype as well:
https://www.defensenews.com/breakin...ll-scale-prototype-of-its-future-fighter-jet/
Now there are American aircraft and technologies which are not properly disclosed to the Public. Even some of the capabilities of F-22A Raptor are not public knowledge.
God knows what Americans will roll out in the future.
I am sure that China will roll out impressive jet fighters of its own in the near future including an advanced LO-compliant bomber type. The Chinese are also producing J-20 in numbers as well as improving them from time-to-time. These designs are good enough to complement Chinese security needs. However, direct comparisons to American products are premature and unnecessary.
The Chinese and American military philosophy and pursuits converge as well as diverge on many counts on the face of it. The Chinese are better off with charting their own course in the aspect of developing weapon systems and solutions as per their security considerations. The game is more about systems than individual designs.
From the link I shared:
"Almost every detail about the aircraft itself will remain a mystery due to the classification of the Next Generation Air Dominance program, the Air Force’s effort for fielding a family of connected air warfare systems that could include fighters, drones and other networked platforms in space or the cyber realm."
All these noises about China are to keep American military industrial complex well-funded.