Wow. I can see these things being caught more often with the growing availability of IR cameras.
I remember a news article a few years back, about the distress the military was having with the idea of widespread proliferation of IR cameras, it was
up there with a 'Millennium project' (for the year 2000) plan to live-stream an image of our spinning Earth. Obviously, someone did not want us to
see something that would have been so obvious.
I took some daytime pictures of these (white orbs) above Vancouver, or at least I think so.