Fighters do 2 points of damage. The same fighter cannot launch and be retrieved in the same turn. However one fighter may be launched while another is retrieved though the same launch tube. Fighters can never be left in a system alone. They must be stored on a ship at the end of a turn.
Any hit destroys a fighter.
Normally a ship can only fire its Beam at one other target ship. This means it can select more than one target. There is nothing to stop the Beams combining to fire on a single ship. This rule simply makes it possible to defend against fighters at a slight cost. As the above rules are just ideas, I have other ones floating in my head.