You can buy fighters and launch them from fighter bays. You can not directly control them, but you can issue them general orders. I assume it would be possible to mod some destroyers and such to be "fighter" hulls (units) so you could get a pseudo-fleet going, though you would be able to "carry" the destroyers.
This could of course just be seen as an abstraction layer for overall fleet command or something. Or it could be like the Highliner SE4 mod.