Watch the Discovery Channel on a regular basis and you'll get to see loads of 'proof'. Unfortunately, different bits of evidence don't really work well together.
Personally, I think that there are either no aliens at all, or that the universe is crawling with them. But there's no reason to assume they are intelligent, older, wiser, better developed or humanoid at all. For all we know we are the oldest in the universe and our UFO's will visit another primitive world one day.
On the other hand, there's no real reason to believe the aliens aren't better developed or practically identical to us.
BTW, if I'm not mistaken, Alien means strange or unknown. I'm no expert on airplanes, and from the ground I can't see who's in it. So I'm actually seeing UFO's and aliens (even on the streets
) each day
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The last arrow of Legolas kindled in the air as it flew,
and plunged burning into the heart of a great wolf-chieftain.
All the others fled. -J.R.R. Tolkien, The Lord of the Rings
