I recently watched Flyboys (I think for the third time). While I think the movie has some problems, I did notice an interesting feature of the composition of the shots during the one sequence that shows the front (when Beagle's plane crashes and Rawlings lands in order to help him).
Aside from shots looking straight from one side to the other (that is, from the perspective of the French soldiers, across No Man's Land, to the German trench or vice versa), the shots of the Germans show them looking left:
And the shots of the French show them looking right:
Not only does this give a visual sense of opposition, but it also shows that the Germans were trying to advance to the west and that the French were trying to push them back east.