When I was visiting La Verkin in south-west Utah, I took quite a lot of photographs in the surrounding area.
Several of the photos show unusual objects in the sky. There is one with a curved shape that we saw many times, over I-15 in Nevada and roughly in a line from the Beaver Dam Mountains east to Hillsdale/Colorado City.
I scanned a photo with one of these things in it and will e-mail it to you ......
The photo is taken from the top of the cliff right behind La Verkin, looking south-west over Hurricane towards St. George. On top right near the clouds is the curved thing we saw many times and the small ball shaped things we only saw a couple of time. Also on right side, just above the horizon there is a vapor trail.