[Kevmo]

And it seems you, dear Kevmo, reject witness testimony as unqualified evidence per se, to be disdained and disregarded.
***Not at all the case. Eyewitnesses are seeing something, but it is a secret weapon rather than extraterrestrial stuff.

I note in passing that both sitings occurred in close proximity to military facilities: the first close by Natick Labs (then an Army research facility); the second, Otis Air Force Base. But I don’t know whether this is germane or mere happenstance.
***It is germane, and it is also quite typical of UFO sightings. It adds weight to my hypothesis and reduces weight from the ET hypothesis.

For the question remains: What is the source of the space aliens?
***There are no aliens. It’s a buncha guys in supersecret craft doing their best to generate the impression they’re from somewhere else. When american pilots were testing the first generation of jet planes, sometimes they put on gorilla suits so that when people reported airplanes without propellers, they would be discredited. It’s standard operating procedure.

Finally, I do not have a clue what UFOs are.
***I do. I’ve been studying it for more than 35 years. It’s difficult to wade through all the piles & piles of baloney. So if you are curious and prefer to be efficient about it, read this one standout book that doesn’t constantly throw Ockham’s Razor under the bus:

Intercept UFO by Renato Vesco
http://www.amazon.com/Intercept-UFO-Renato-Vesco/dp/B0006WI572

[betty boop]

There are no aliens. It’s a buncha guys in supersecret craft doing their best to generate the impression they’re from somewhere else. When american pilots were testing the first generation of jet planes, sometimes they put on gorilla suits so that when people reported airplanes without propellers, they would be discredited. It’s standard operating procedure.

I think it's safe to say, dear Kevmo, that you have a strong conjecture that reports of "alien sitings" are "side shows"; and that the U.S. military is involved with propagating such false reports. You may be right about this!

So you definitely go on my little list of potentially credible alternatives to the standard space alien/UFO myth that has been widely propagated in our society, thanks to speculations about Area 51 and its "contents."...

Anyhoot, at the time I heard the accounts just described, I quite independently took notice of the fact that U.S. military installations were then close-by, from simple recollection of contemporaneous local knowledge.

This probably puts me closer to your strong conjecture than I am to the standard Area 51 claims.

Thank you ever so much for writing, dear brother Kevmo!