The aeronautical capabilities these ‘things’ possess far exceed not only our own aeronautical capabilities, but exceed the laws of physics as we currently understand them.
If there’s a country out there that has developed this tech, it would be EXACTLY analogous to a country, in secret, having functional space program at the time two French guys took their first hot-air balloon flight in the late 18th century. That’s the kind of technology delta between what whatever these things are and what we’re currently capable of.
Does that sound plausible to you?
You assume that these things are aircraft. I assume that they are projections of some sort, rather than aircraft. Regardless, it’s guaranteed to be the work of Uncle Sam.