I think this is a good forum. I do not think aliens exist as Hollywood teach. The Bible says there are other worlds with people on them, but they are unfallen worlds. They have not fallen into sin like our world and do not need spaceships to fly.
There's a whole universe that's still to be explored, including several circling similar suns to our own, it's impossible to say that there is not at least one other planet out there that supports life in the same way our world does.
From a scientific viewpoint it would impossible to say that humans are the only form of sentient beings in the universe.
From a spiritual viewpoint it would be arrogant, prideful, and even foolish to think that when God made the universe that we were the only beings that He created.
From a psychological viewpoint, man has always been self centered and viewed themselves as the center of all things. Early maps of the universe demonstrates this quite well with earth being thought of as the center planet that stood still while everything else revolved around it (including the sun). As science developed and more knowledge became available then it eventually became clear that we not the center of all things, but instead are the 3rd planet in a solar system among uncountable billions of other systems within a single galaxy of a universe composed of uncountable galaxies.