Extraterrestrial Hypothesis

The prevailing Extraterrestrial Hypothesis that some UFO sightings be craft from other worlds, but where is evidence of such for us. I believe we are dealing with creatures that are extra dimensional in manner. OK, this can explain the absence of any crashed craft in our universe. Well, we are not saying that the Extraterrestrial Hypothesis is wrong. However, I feel this does not explain what we are seeing.