UFOs From Ancient Times

The Sumerians speak of "gods" visiting from the heavens. Could it be that these were, in fact, extraterrestrials, aliens, borne on UFOs, visiting our ancient ancestors repeatedly? And why is it that Egyptians and other ancient civilizations have similar myths and religious beliefs? Is it possible that we are descendants of both Man and Alien? Could it be that evolution took a giant leap sideways with the introduction of an alien race, come to Earth in spacecraft, bringing with them technology never seen before and not repeated since? The evidence can't be denied.