I can easily imagine how some of these phenomena could be puzzling to the average city, or even country, dweller, but should experienced pilots and air crew be making the same mistakes - repeatedly?
Yes, or of course other UFO spotters may have looked at their observations critically but cannot find a simple explanation (this can be the case even in the absence of little green men).
In my case the most likely explanation for what I saw was an illuminated blimp, and certainly that’s been my assumption. But there are aspects of my observation that don’t quite fit and so I haven’t had an “aha!” moment.
The mechanism is not definitively known, but one explanation involves tectonic stresses on quartz-bearing rock, causing the emission of plasma effects due to the piezo-electric effect, not unlike the sparks generated when wintergreen Certs are crushed between the teeth.
Sure. They’re just people and are just as susceptible to visual illusions, fuzzy thinking, confirmation bias, superstition, and all those other things that make people mistake the ordinary for the extraordinary.
I think you only have the “aha!” moment if your brain resolves the illusion at the time. Just like when you’re looking at a picture of an old crone and you suddenly realise it’s also a picture of a beautiful woman. If whatever you’re looking at doesn’t resolve itself to something mundane and recognisable at the time then you will always wonder what it was unless you get a chance to see it again.
Edit: And often it’s not an “illusion” that you can resolve, you may just be looking at something you’ve never seen before (such as an exploding Russian missile.)
I saw one of those when I was a kid: a ship, floating upside down in the air above itself. very weird. I was not tempted to think it was an alien craft, though. It was clearly shaped like a regular ship. I could see the funnel.
Yes, this is a very scary phenomena, saw it with Venus once. You make some excellent points.
Even though it is not what the OP asked about, I think it is important to clarify that many UFO sightings are just that - sightings of unidentified flying objects. That is what the pilots I interviewed on the topic talked about. They said nothing in their training taught them about craft or phenomena beyond what they are expected to encounter - so they report them as UFOs. That in no way implies an alien source.
Many sightings are of aircraft which are not known - the testing of prototype blimps and other craft, such as weather balloons - is done near ground level. I wrote about that in my book, finding the most fascinating aspect the research was into Area 51 in Nevada, where a great deal on commercial and military testing of craft goes on in secret. Secret for commercial and military reasons. Just think about all the testing of early stages of the stealth bomber and you’ll understand what I mean.
As a hard-nosed skeptic, may I add that nothing here proves there are not alien visits. Our current understanding of physics makes it seem unlikely, just because of the energy requirements to get a physical craft across such massive distances. But I can’t imagine anything more exciting than contact with an alien intelligent race. Even just to make communication contact would be incredible!
I cannot prove there is not an invisible BoogieMan under my bed, either. Should I be worried?
In Michigan ,many years ago, there were a lot of saucer sightings. They concluded it was were swamp gas. If you buy that explanation then yes, it can be atmospheric conditions.
Yes. Be afraid. Be very afraid.
No seriously, it’s true that we can’t prove a negative. But “a nonzero possibility exists” is not the same as “look out they’re probably here”. 
Only if you believe in invisible Boogiemen. I do believe there is a reasonable chance of alien intelligence somewhere in the universe, but I don’t know if they exist. I don’t believe there is a reasonable chance of invisible BoogieMen.
Another unusual aspect of these (which may add to the perception that they might be “alien”) is that they only exist in windy conditions, yet are pretty much stationary with respect to the ground. They are continuously forming at the upwind edge and dissipating at the downwind edge.
What about members of the different military organisations on bases throughout the world? Should they be a bit more familiar with what might be traversing our skies?
Are you suggesting they should be aware of and able to identify on sight, even in the worst of condistions, every possible airborne man-made object or natural phenomenon? They should be aware of unannounced satellite launches and should be experts on identifying that extremely rare mix of atmospheric conditions, your ball lightning reflected off swamp gas in the moonlight of a hazy night?
Truth is, there are innumerable possibilities for what can been seen and how it is perceived in a particular location, the optical reflections unique to a certain physical environment, etc. There is just too much out there to be able to know and identify any given anomaly just on sight and at the very moment it is happening. It seems you are pushing towards the conclusion that military members should not be fooled by simple phenomenon and thus that more weight should be given to their accounts. I don’t think this is a valid line of thought and hope that I am just reading too much into your motive.
I’d certainly expect those who worked on an air base or as fighter pilots, to know the difference between the planet Venus, and an intelligently piloted craft… wouldn’t you?
They’re still human and still subject to being mistaken, at least in unusual or inclement weather conditions. Also they may be under a lot of stress which would only add to the ability to become confused.
I’m sure they are able to tell the difference in 99 out of 100 cases, but for the one time when it’s extra hazy, there’s a fog rolling in, or some other confounding circumstance, they can and certainly are able to be fooled by mundane events. I think it’s absurd to think that just because someone is a member of the Air Force that they are all of a sudden infallible observers.
Nope, there are plenty of instances of trained pilots think that a UFO that turned out to be Venus was chasing or running away from them.
They see a light, and the light appears to react with their maneuvers, so they react as if it did. Venus certainly can appear to act just like it’s chasing or running away from you.
And when it happens in clear skies and more than one reasonably qualified person sees it?
Any examples of the sort of thing these people might be experiencing?
I’ll settle for pics or preferably video footage of such events given as explanations above, if you can provide them.
Well, in that case, the only reasonable explanation that persists is, of course, that little grey dudes with outsized heads and eyeballs travelled billions of miles through the vast emptiness of space in a dingy piece of dishware, expending energy and resources we don’t even have a conception of, just to amuse themselves with a couple of erratic manoeuvres across our sky for no apparent reason at all.
Yes, I know, they’re aliens, so who knows what they might consider sensible – but the point is that even if you exclude all atmospheric phenomena, artificial and natural crafts you know of, anything else you can think of, the hypothesis that it’s actually aliens on some interstellar joyride is still so unlikely that the evidence just not justifies its serious consideration. See, it’s not ‘either you can explain it, or it’s aliens’; even if you, or I, or any number of experts can’t come up with an explanation for some particular photo or video that you consider satisfying, that just means that nobody’s come up with an explanation so far, nothing more.
Think of magic tricks – if you’re not far better versed in the art than I am, a great many of them will probably stump you as much as me. But that doesn’t mean that there’s actual magic involved, and even if some particularly clever magician devises an illusion so brilliant that all of his colleagues can only scratch their heads, you’d still probably just consider it a particularly clever trick, nothing more. And compared with what mother nature has up her sleeve, even the bag of tricks of the greatest magician seems pretty piddling.
You won’t get a list of things to cross out in order to judge some particular UFO sighting genuine; and even if you had such a list, crossing everything on it out would only tell you that it’s something not on your list. Sure, it might be the case that there’s actual aliens inside some pixellated blob hosted on some badly designed website, but then again, it might be that some magician that performs particularly hard to explain illusions simply uses actual magic; but in both cases, that should not be the first hypothesis to turn to, even if you’ve exploited all other options you can think of.