btw iirc from what challenger said, haegemonia uses an autolod system
actually I have no idea about how a game engine can modify a mesh in order to generate lods without wasting too resources, but this explain why it is possible to put such hi pcount ships in game (althought I consider them a bit inefficent)
Btw you can put those model (at least the models of small ships) in fs2 too, just work with lods: put the hipoly mesh as lod0 with a very close visible range (so you see it only in external view or flying very close) and make normal lods for all the other situations. Obviously this doesn't mean I'm going to do it:)