Sunlight glinting off the aircraft.
Airliners are very shiny, have lots of windows.
It’s also illuminated by orange sunset sunshine while it passes in front of a darker part of the sky making it appear to glow.
It’s an airliner.
And this will happen again one day as it did similarly the next day.
I’ve seen this before ok? I am a private pilot in SoCal of and on since the mid eighties.
Yes it makes you look twice.
But there is so much evidence now there is zero doubt it was an airliner.
I am surprised people are having a hard time with that.
Rational thought should prevail.
TWA 800. That's why.