Most of the UFO sightings occurred around 8:15-9:00 PM, while the flairs were known to be ignited around 10:00 - 10:30 PM. Really bizarre fact about the Phoenix lights, the Governor of Arizona at that time has admitted he saw the UFO (UAP - whatever) [0].
"Easily explained" is not really cutting it for a lot of people. And that's cool. That's part of the difficulty with this, everyone has different thresholds where they're convinced about something which basically none of us have any idea is. What's "easily explained" for guy X might be "way too convenient" for gal Y. ;p ;)x
[0] https://www.amazon.com/UFOs-Generals-Pilots-Government-Offic...