I prefer to believe they're only RC aircraft rather than aliens.
In any event, you can only see them when they slow down and land over near 56th Ave. and Clay Street in Denver between noon and one.
Is there a restaurant near there? Maybe it's their lunch time.....
“The flash of light you saw in the sky was not a UFO. Swamp gas from a weather balloon was trapped in a thermal pocket and reflected the light from Venus.”
M.I.B.