[nihilix]

Yes, fighters do slow you a bit. The lack of speed is, imho, more than made up for by the ability to distract most enemies and allow your big ships to pound them into glowing space dust. (Hint - give your fighters the fastest thrusters possible - Ion Impulser is the best they can take)

Fleet speed is weighted, however, so the non-drive fighters don't slow you down too much. This does mean, however, that you should always give your fastest drive to your largest ship! If you have the Grav drive, and your flotilla is the Terran Frigate and the Moon Marauder, give the Grav to the frigate, not the Marauder. Swap them around, and you'll see what I mean.