Who here believes some UFO's are alien craft?

Not me.

Given the vast amount of reported UFOs that are subsequently identified as normal astronomical phenomenon, normal meteorological phenomenon, military aircraft, or human spacecraft... and the ones that remain unidentified being so because the testimony of the observer is so vague and inconsistent, and the fact that meteorologists and astronomers have never reported any (these are the people who spend the most time looking at the sky, they should be reporting the greatest number, but they don't, because they are familiar with what they are seeing), and the distances required to travel through interstellar space, I seriously doubt that any reported UFOs are alien in origin.

Technically, alien life does exist. Taking the size of the universe into account, with all the planets in it, it is certain that there is alien life. However, the distances are too great for any spacecraft, even for something moving .0000001 km away from the speed of light, to get anywhere. Furthermore, evolution happens at the same rate and for the same reasons, so aliens would look just like us. There is no need for evolution to create blue skinned creatures on three legs.

I'm sure they already have made contact with governments around the world many years ago. Why would the government tell us if they had. Although if they haven't yet, according to stephen hawking,"considering how big the universe is, it is almost statistically impossible that advanced alien life does not exist".

UFOs-Unidentified Flying Objects, is that it can not be Identified. The short end of the stick is, the possibility other being from other sectors of the universe- travel of using as we call- a Wormhole.So the chances are, if your opened minded- yes more then .0000001 percent chance.

I do believe extraterrestrials are watching us because we are at a critical point in our existence. Humans are no different now than we were two hundred years ago. We are unpredictable, socially unstable and commit unspeakable acts of cruelty towards one another. To aliens were are not much better than lions who have technological ability to destroy each other. If I was them I would keep my distance also.

Only those with no real grasp of the size of the Universe or the laws of physics.

One would think that if they were trying to stay hidden, they would remember to turn their running lights off. One would think that if they weren't worried about being detected, they wouldn't shy from contact.

Aliens should stay out of sight. If we can figure out where they are coming from, we will invade them.

They must see us as Neanderthals, power hungry beings who are just interested in attaining material things and power, fighting each other like a pack of hungry wolves, Earth must compare to a thug ghetto in the Galactic worlds, they steer clear of us hoping we hurry and destroy ourselves so their off-springs won't have to deal with our need for greed and conquering ways in a few thousand years.

That is a question people have been struggling with for years and years. The list of who is who in UFOlogy is pretty impressive though - http://www.ufo-gifts.com/ufology-whos-who.htm