Google Earth is a snapshot, or rather of series of snapshots, that covers the globe. So, if there were anything suspicious in the line of UFO activity, it should have been captured by the process (assuming, of course,that anything found wasn't scrubbed by the military long before the images were released).
Going with the theory that something could have been picked up, we have a video showing what appears to be UFOs present in the sky shots from Google Earth.
