Bob McDob said:
Maybe Confed agreed to let them keep it in exchange for trying to exterminate their entire nation, and all.
Confed can easily put the political blame on Tolwyn and rid themselves of any guilt, Senator Taggart did this well by acknowledging full freedom of the press in Tolwyn's Court Martial, rather then doing the traditional "The Fleet takes care of their own".
Another problem is the crew and the fighter complement. Is that going to stay in BW service? Since some of the crew signed up with Blair, will they be charged as traitors, or prisoners of war, or will they have to go through Captain's Mast and a court martial? What about the fighter complement? Will that be withdrawn back to Confed, or will Confed just give out government handouts and let them take it all for free?
I can seriously see leasing ships over to them and vice versa though. For example, let the Border Worlds lease the Princeton for a few years to help what's left of their forces and get them up and running, while the Intrepid was used as a training carrier (at the end of WC4). But in all due time, they'll have to be withdrawn back to their original services.
But if this isn't satisfying, we an always use the WC Aces liberal interpretation and say that the BWs can build their own fleet carriers and uberfighters, because they just magically pulled enough money out of their asses. And of course, assuming that any shipyards they build (the Border Worlds are in the buffer zone between Confed and the Kilrathi), will just be ignored and get classified as a low priority target when the Kats decide to cross into the border for a nice raid.
Kat 1: "hey, isn't that Border World shipyard a high priority target?"
Kat 2: "no! even though the Border Worlders are fools to put a major shipyard this close to the border, let's ignore it so we'll give them the chance to build their own fleet carriers!"
Kat 1: "yeah! So what do we attack?"
Kat 2: "let's attack that unmanned drone over there! it's a lot better target for our raids"