If aliens have the ability to travel great distances if at all, I am pretty sure that they would have the technology to conceal themselves relatively well too.
We are still in the dark ages of science but increasing knowledge quickly.
So many theories can be thought of some outlandish some responsible. Irrespective it would be great to keep an open mind on the subject.
Sometimes i see things but cannot for say be certain they are other life or whether it is those furry thing that float in my eyes that are playing tricks.