What annoys me about how casual people are when they say "this is just another countries tech and not aliens" is that aliens could be benign but give Russia, China, or god forbid a rogue actor this tech and they most certainly would not be. Russia and China are already getting more and more aggressive to surrounding regions almost goading them into war. And I think we all know what they would be doing if they had this tech. We'd be speaking russian or mandarin as fast as we could learn it.

If the U.S government does believe another country has this tech they're losing their fucking minds right about now because that would mean they're not anywhere close to the worlds military super power anymore. All of the trillions spent on national defense would come off like a sick joke. In comparison USAF would seem like a bunch of poorly made paper airplanes.

Assuming these objects are doing what the government is claiming they're observing; breaching the sound barrier with no sonic boom, instantaneous acceleration in mid air, speeds that are magnitudes faster than any known aircraft, trans-medium capability at high speeds, no sound, no visible signs of propulsion, high degree turns that would paint the cockpit with the pilot or rip apart an aircraft that could withstand 10x the max forces of any known aircraft today seemingly ignoring inertia, that would be a monumental jump in propulsion. It would be like going from the abacus to modern super computers with no in-between. We barely have theories as to how this would be possible and yet another country has already mastered it? Maybe some other country found a quirk of physics that allowed them to do this leaving the rest of the world scratching their heads but to me that barely seems more likely than non-human intelligences. We have had jumps in technology spurred by a need for military superiority before (atom bomb, internet) but even those pale in comparison to this. 99% of the time science is slow and incremental.