My own scepticism of the alien interpretation of UFO's began when I was a teenager. I read a couple of George Adamski's books.
George Adamski - Wikipedia, the free encyclopedia
Then I read an expose of Adamski's books, written by a sceptical person. I realised that I was an idiot to take that crackpot's writings seriously. I also realised from that expose that each and every photo in Adamski's books had been faked. The expose even explained how to fake photos like that, and included a number of such fakes.
Even though I was thoroughly disillusioned, I kept an interest in the subject and I have read of a number of alternative explanations for people's experiences. If you have full information, it is not too hard to find mundane explanations.
For example : any report by individuals (or even small groups) which are eye witness accounts - well, to take them seriously you have to assume that the person(s) recounting the sightings are not :
1. Hoaxers
2. Liars
3. Nutters
4. Dreamers.
That is an assumption that cannot be made, unless there is overwhelming independent evidence.
Another point is that no memory of something dramatic like a UFO, that is more than a few years old, can be considered reliable. Like the trout that grew, UFO stories change in the repeated telling. This does not represent dishonesty. Just the normal fact that human memory is malleable.
There are often clues. Procrastinator's story is almost certainly an aircraft. The flashing light is an absolute give-away. Scramble describes a group of oval lights flashing across the sky in tight formation. That is utterly characteristic of a nearby light reflected off a window glass or similar. Small movement of the reflector translates into apparent rapid speed 'across the sky.'
In the same way, I suspect that Starbeast's black object was probably a 'floater', and the memory of a relatively trivial event has been magnified by the modified memory that comes of retelling a story many times.
None of my explanations, of course, are certain, since I do not have all the facts, and I cannot run any test to check my hypotheses. However, the "aliens are with us" hypothesis seems much, much, less likely.