KCRA, Channel 3 in Sacramento was interviewing someone in Diamond Springs, a suburb of Placerville which is considerably west and north of the Owens Valley and Las Vegas. At the same time they were showing the trajectory going right over Sacramento and Placerville, south east toward Texas and Florida.
The individual was watching at 5:58 PST as it passed over and as it headed toward the Sierra horizon before sunrise, he could see things that "looked like the shuttle was dropping flares!" They interviewed a couple of others that like this guy, claimed to hear something that didn't sound like the typical sonic boom the shuttle has made in past approaches.
They described as sort of a pop-thud, very brief and not as loud as a sonic boom.
I didn't post this as a challenge to your attitude of certitude and I have no idea if these televised interviews of civilians is even worthy of anyone's consideration. But I know I've witnessed things that were not UFO's or even tinfoil hat stuff that turned out to be verified later to the consternation of "experts" and those obsessed with "conventional wisdom."
Hell, I was in the firing room there when the challenger was lost, and had no idea what had happened until I got back to my motel several hours later and turned on the news.