: Well, the largest "normal" ship in Halo. The Forerunner stuff
: starts getting real huge too, but especially since those are apparently
: far more automated than your average human or Covenant ship, as well as
: the fact that their tech is still out of reach for us mere mortals, makes
: it more forgivable. The only forerunner construct that starts getting
: really ridiculous is probably Trevelyan (large enough that it swallowed up
: its sun and planets when it came back to real space!) but things like
: Mantle's Approach are still huge (300-ish kilometers on its longest axis.)

Well it's pretty easy to make absurdly large stuff when you can turn light into a matter-like substance.