I don't have my copies of the books infront me at the moment but on the subject of atmospheric combat and weapons I think it mentions in Action Staion and End Run that fighters and bombers had special ordanance loadouts for atmospheric missions. For example I think remember Bear taking out a number of ground targets using a missiles that homed in on enemy radars (IFF?) and enemy targets using comms similar to HARM missiles. Also I think these missiles had MIRV warheards that worked with his Rapiers onboard computer to prioritse targets and switch targets to any that might be destroyed before the warheads destroyed thier original targets. Also some Kilrathi ground stations and defences stopped broadcasting or using radar to avoid being taken out by these missiles on Vukar Tag. What missiles were these?
I think I also remember reading somewher that anti-matter bombs were used by bombers/fighters in the atmosphere aswell. So fighters don't just have to rely on the weapons that they would use in space to fight in the atmosphere against other airbourne targets or during ground support and bombing missions on a planet.
Another thing. In End Run. Wasn't the major reason that the attack on the Kilrathi fleet was such a major success was beacause the majority of the Kilrathi fleet was commited to ground ops to retake the planet with the Kilrathi fighters loadouts set up for ground attack and ground support so that when the confed fleet came through they weren't realy in a position to either defend against confed fighters or launch a strike against the confed fleet because they were armed with bombs instead of torpedoes.
As I said though I haven't got the books infront of me and its been a while since I have read them so my memory is bit sketchy so let me know if im wrong or way off base