Personally, I think that there are different kinds of UFOs. Some I think can be explained by natural phenomonons, while others are piloted by intelligent life. The most intersting UFOs to me, are those that I call Zippers. (because they travel at unbeleivable speeds and seem to defy physics) These crafts, I beleive came to earth interdimensionally, from alien civilivations. I also have a hunch that a deal was struck with the govt in the 60s, where we allowed certain priveleges for advanced technology.
I also beleive that the govt has in it's fleet ships similar to the Alien 'Zippers', and that some sightings are 'test-drives' of their new crafts.
I also still beleive that aliens do inhabit, and visit our planet, some in underground facilities, and possibly even amongst us. (far fetched, but a boy can dream, cant he?)
Here's a cool video of a sighting from Bulgaria.. Watch the ending.
Here's another interesting Zipper from Area 51 in 1990.
Area51 UFO Vid
Credit: we-are-believe.blogspot.com
