I'm a newb at this - just AI only so far, but fighter survivability is a bit low for my tastes. I don't use hangars anymore - I find my tactical slots and resources are better used elsewhere - mostly ships, repairers, jump inhibitors and a few turrets if I have the slots to spare. By late game, culture dissemination is rather nice. On my cap ships I go with 100% bombers for good damage and survivability and use flak frigates for dealing with strikecraft. I'd rather have flak frigates over fighter squadrons anyday.
My standard fleets have a battleship, carrier, buffer cruisers, lrms and flak - eg for Advent, Radiance, Mothership, Guardians, Illuminators and Defense Craft. I keep one fleet guarding each choke point with my empire safely behind. Even without caps, it's amazing what a few Guardians, Illuminators and Defense craft can not only hold off, but completely destroy with the aid of a few repairers and a jump inhibitor.