Theories on UFO's and alien civilization's

[rzr]

I was thinking, when people see an alien spaceship it always leaves immediately. They never really attempt to destroy us or hurt mankind (or so is said). So is it possible that those "UFO's" are us?

What i mean is: say a thousand years into the future us humans gigure out time travel. Isn't it possible that the "aliens" we see visiting us now could just be us a thousand years into the future, coming back in time, to check up on us?

That part is possible because our survival is crucial to theirs.

And notice there were alligations in the 50's about the "aliens" assisting in the production of government technology. But they have never hurt us, because of my above mentioned theory.

What does the rest of the world think, is this a possibility no matter how slim the chance be?