UFO ... or? The Strange "Row of Lights"?

In October 2021 in Sedona my husband and I saw a mysterious row of bright equidistant lights flashing back and forth above a nearby mountain, Sugar Loaf, which was wider than its top and clearly not hikers with flashlights nor satellites nor anything we recognized.) Not even a UFO, in that it never moved, but just went dark. Then it turns out at least 4 friends have seen the same kind of thing at other times or places. Never seen this in UFO lore before. So what the heck was THAT?????