A question for science fiction fans?

When two spaceships meet in a star wars/trek film why are they always both the same way up?, what are they flying level with....the horizon?
Answer
Now i am going to worry all day about which way is up in outer space. i know how to do it if overtaken by an avalanche but dribbling to see it it runs down your chin or up your nose probably is not acceptable on a space ship :-))