Do the people who believe Ufo's are aliens have any idea at all how big space is? With a 100 billion stars in our galaxy alone, life elsewhere is almost inevitable. How are they even going to find us? Are they even looking? The needle in the haystack analogy doesn't even come close. And I'm not even mentioning traversing the huge distances involved. And why is it that people who know most about the sky, like astronomers, report the least amount of Ufo's? Well with people reporting the planets Venus and Jupiter and even the freaking moon as Ufo's that one shouldn't be hard to answer.
The possibilities are endless when you think about the amount of time that we have been around ( 200,000 years ) + the technological improvements even 1000 years can bring