One of the Eagles seen taking off to fight the alien spaceships in the heat of battle is a Medical Eagle (from its red stripes on the side) which aren't equipped to fight using lasers. At that stage and from the script it is clear that using the few launchpads to launch fighter Eagles is an imperative rather than Medical ones (e.g. to rescue stricken Eagle crews whose deadly fate is obvious).
The model for the Mark IX Hawk has a small blinking light on the ventral side (the "chin" of the command module). These are used to sync laser SFX in post-production. Unlike the Eagle's lasers, no "beam effect" was added in post-production for the Hawks firing their weapon.