>"The disc was visible for approximately five minutes and was seen by close to a dozen United Airlines employees, ranging from pilots to supervisors, who heard chatter on the radio and raced out to view it."
It also apparently was not visible on radar or visually from the control tower. Who cares if it was 'aliens' or not, it's a damned interesting phenomena that should be studied for it's own sake.
Not taking a side, just pointing that out.
And Someone allegedly photographed it, but no one bothered to examine or release the photos?
The vast majority of people are looking at Venus or the moon or streetlights or drunken hallucinations. But we don't care about those people. We care about the 0.0003% (or whatever) of people that check all the boxes on a long list of reliability factors. And yet, that still isn't good enough for some people, because of the hugely negative pseudoscience context that this carries with it. "It's folklore!" In fact, I'll assert that a strange enough advanced aircraft could fly nuclear weapons over this country, and until our pilots shot it out of the sky and spread the wreckage across three states, it would hardly get any attention because of the context this subject carries.
[0] https://en.wikipedia.org/wiki/J._Allen_Hynek#Change_of_opini...
I'm not saying it was an alien craft, but there are a limited number of plausible explanations for an event like this and none of what you listed is a plausible explanation.