OK.
There are numerous threads here on UFOs in dreams.
They are in our culture, our popular awareness... our phyches. And they are in our dreams.
It's a question of fact, though, what they are.
But knowing where they are, helps.
Part of the answer is: UFOs have apparently also ever been with us. They are very much a part of art, through the ages.
To begin to see: http://www.crystalinks.com/ufohistory.html
PQ