Thats why I really like the newer general term, non-human intelligence. I believe it was Lesile Kean who said that on some retrievals, there were no occupants to be found, almost insinuating drone'ish like craft that just landed. I really think the biggest issue is that it is automatically assumed that UFO's = ET's and this is why NASA and AARO can say "no evidence of extra terrestrial life has been found." In reality, it makes more sense these are interdimensional and why whatever it is, seems to have an interest in our nuclear capability. Perhaps their survival depends on ours and why sightings in the USA and Russia shot through the roof after WWII.