it is quite plainly an exploit too summon more pets by swapping out hangers - the pets should be de-spawning when the hanger is swapped out - however the entire pet mechanism needs reworking - pets need buffing and the carrier needs to be able to use the kind of pet commands most MMO's tout (defend me, attack target, return to me etc)

Carriers are wierd, the only thing that I can see that makes them anywhere close to overpowered is when you have multiple of them exploiting to get multiple ships that they should not have, and even then its no real biggie. in small numbers like they were designed for, those ships are fairly weak and do need modification to be a threat. they're also slow, unmanueverable and if you take them the pets despawn.