In an interview on The Skeptics Guide to the Universe (https://www.theskepticsguide.org/podcasts/episode-829), West explains that part of the reason the Defense Department cannot explain these videos is rather pedestrian: the systems in use are classified. Quoting from the transcript (https://www.sgutranscripts.org/wiki/SGU_Episode_829):

"The problem is that the military don’t want to talk about this, partly because this is a classified system that these are recorded on. It’s called the Raytheon ATFLIR system. And it’s a fairly advanced targeting pod that straps on underneath the planes. And if you look for example videos shot with this on YouTube, you will find, basically, nothing—like a few really grainy ones, because even though I’m sure there’s tens of thousands of hours that have been shot with it, it’s all classified. So they don’t want to talk about it. And if they do analysis of it, that becomes classified by default. So they’re not going to release it. And they’ve actually explicitly said that they do not plan to release the results of the investigation into these videos."