The Telegraph is running this (so not a particularly reliable source) but it got me thinking
I tried to review what I know about UFOs, from the basics, which is that there apparently exists a large collection of films, photographs and videos, and of reports from observers of varying degrees of credibility, of what they've seen or think they've seen in the sky, and no one is sure what any particular image shows or what anyone actually saw, but whatever it was, nothing seems to have happened because of this object, whatever it was, and since then, nothing.
So we've got what appear to be objects of various shapes and sizes and no one can say what they are, so all we can say is that they appear to be objects of some sort, and since they're up in the air and don't seem to be falling, they must be either flying or floating, but that's about all we make out.
Fair enough, but how do you get from that to space aliens?
I mean, if someone shows me a picture of something that certainly looks like a saucer-shaped object in the sky, just as some clouds or pieces of toast certainly look like faces, then why on earth would I entertain the possibility that it it's a vehicle that's somehow arrived from some impossibly vast distance and then vanished, rather decide that we don't know what it is simply because we don't have sufficient evidence, context, or understanding of the psychology of cognition and visual perception to make sense of what we're seeing?
Obviously the military need to study this kind of image closely, because if whatever it shows belongs to the military of another country, then they want to know about it, and if it's something belonging to the Russians or Chinese they've never seen before then that needs urgent investigation, and similarly NASA and air traffic control want to know about it, too.
But if at the end of it all, all the experts say, "Nope, no idea what it is, but doesn't seem a particular problem, at least for us, at the moment," then OK, then we've got some image that we can't make sense of. What follows?
A particular image or video might show all manner of things, but if we start to entertain possibilities that defy what we know of the laws of physics, then maybe it's a fire-breathing dragon or a witch on a broomstick. How can we tell?
Nope, no idea what it is. Does it matter?