how much do we really know about Ufo/ebe's?

there is alot of speculation regarding the ufo phenomena but how much do we really know and how much can we prove beyond reasonable doubt.We know that many people believe to have seen strange anomilies in the sky of which we have many picture/videos but only a small fraction of these are imposible to debunk through rational study and examination.We Know that many experiance what we have come to know as abductions but many skeptics regard these happenings as Sleep paralysis or Hypnagogia.So wht evidence do we have for the existance of UFO's?I don't think we have enough information to reack a REAL conclusion.

sorry for the bad spelling