It's a lame excuse. Go to google images and do a search for "lenticular cloud". Most commonly they are associated with mountains and high wind conditions. The cloud itself can be relatively stationary even in the high winds - it has something to do with a standing pressure wave set up by the terrain (see wikipedia on
Lenticular Cloud). So, it can be odd to see a cloud "hover" like that, but locals see them all the time and know what they are. Because lenticular cloud formation is dependent on terrain and wind conditions, using that as an excuse for a UFO sighting in an area where they don't normally occur is simply bogus.