Well first off, the reason you remember more dreams when you come to places like this and write them down, or write them down in a book, is because by doing this you are telling your brain that you want to remember them. The best way for anyone to remember their dreams better is to actively try to remember them by writing whatever they do remember on a piece of paper, and drawing pictures if they like. A lit of the time people don’t remember all their dream because the brain doesn’t think you want to/need to remember them, but it decides that you do after all if you write them down when you’re awake – just as if you were studying for an exam that is important to you, your brain will try to help you remember all the important information.

As for the dream it depends what aliens mean to you, for some it could mean a fear of strange and new things; or, if you like the idea of alien visitors, it could represent an excitement about strange and new things. It could be that you are worried about outside influences coming into your life and changing everything without you being able to do anything about it, yet you still sort things out yourself in the end. There are lots of alien invasion type movies around, and have been for quite some decades now, so you could be living a movie fantasy adventure, but what I said about outside influences altering your life could still be true even if this is the case. The sleeping mind or unconscious is all about imagery and themes, your brain knows how aliens make you feel on a subconscious level when you watch sci-fi movies or whatever, so it uses the images of aliens, or the theme of aliens to try and communicate to you the feelings it thinks you attach to them.