The US does an incredible amount of signals intelligence on China. Even if the discussions between the ground controllers and aricraft were encrypted rather than transmitted in the clear there would be a noticable spike in them and out sigint satellites would be able to determine the location.
Analysis pointing circumstantially to a shootdown scenario wouldn’t be too difficult. Once the Crays in the basement of Ft Meade got to work on the encryption (and we’re probably not talking about that difficult encryption to break here) the analysis would soon point to probable ...
They still use Crays?
I thought the latest supercomputers were IBM?
Ed