Originally Posted by Iamme
You can when there're trade routes between the planets (which are always illuminated) or when you're selecting what planet to move to it will show the route.
What you say is true, but when I'm deciding what planets to garrison, I don't want to be forced to select a fleet (if I have one) and drag it around the map so that I can see the lanes of travel. The general rule of thumb you mentioned has some exceptions that are not clear or intuitive just by looking at the map. Are you saying that you wouldn't like a show/hide option in the game settings? :-)