My first reaction on seeing this Google Maps zoomed-in sat photo was “OMG MISSILE OVER UTAH MUST SEND LINK TO EVERYONE” but OKCalvin has set me aright by pointing out that cruise missiles don’t have dual contrails, and that closer examination of the object shows that its wings are dark against the background:

Sure enough, someone on this Airliners.net forum entry is pretty sure it’s a Mesa Air CRJ-900, with dark green wings and tail. I am, as usual, late to the party. (AIM transcript in the comments.)