If anything an airlock isn't necessary. Pilots do not eject and separate from their seats like in modern fighters. They remain in a pod that is then retrieved. In some cases the pod is then tractored onto a weapons hardpoint for return to base.
Well, even in WCP, where pilots really do eject in pods (which is not the case at all in 2667, mind you - and might not have been in 2669 either), when a pilot does get dragged in by an S&R ship, we see him brought onto the Midway in a stretcher. We know that pilots in general can be injured during ejection (happened to Blair, happened to the guy who wrote the Academy manual). So, probably an airlock is a must, in order to be able to check in on the rescued pilot.
You argue that the Thunderbolt might well have a tractor beam, but you don't address whether or not it has an airlock. The Thunderbolt is 34 metres long, and, if the proportions on the WC3 fighter selection screen are correct, slightly under 20 metres wide and 8 metres high. These dimensions are large enough to accomodate an airlock designed for the retrieval of pilots (probably a cylinder 2.5 metres long with a 1 metre radius or thereabouts), but such a feature is large enough that it ought to be apparent on the ship's surface, which it is not - unless, I suppose, the Confederation logos on the flat surfaces near the engines in the standard wartime paintjob also conceal the airlock seal. I do not think the Thunderbolt design has an airlock, but I can't prove it.
We certainly can't prove it either way, but it doesn't strike me as something that needs to be proven - we have no problem accepting that the Sabre has an airlock, though it's much smaller than the Thunderbolt, and the location of the airlock is certainly not obvious on the ship model. It's a secondary issue anyway - if we had any real evidence to confirm that HF means what it would under US designations (which we don't), that in itself would be proof that the Thunderbolt has all it needs for the role. Without this, there's no point trying to prove that the Thunderbolt has or hasn't an airlock.
The biggest factor that I think might well have lead to greater standardisation in Confederation equipment (both in terms of fighters and components) is the length of the war. World War II lasted six years (if you're British or German) or four (if you're Russian or American), whereas the Terran-Kilrathi conflict went on for over 30 (though I don't believe we have any conclusive evidence one way or the other as to whether it was a high-intensity conflict for that entire time, which I rather doubt). Over that period of time it would be expected that (especially with a degree of government control over the economy, something President Rodham mentions in passing in Fleet Action) there would be a move towards standardisation of as many components as possible.
I see no reason to believe that. Why would this be the case? What we saw in WWII was exactly the opposite - as the war progressed, there was more and more diversification. It's peacetime that tends to lead to standardisation, while at war, a multitude of different tasks demands a multitude of different fighters. In addition, I don't think it's ever implied that "government control" means anything different here than it did in WWII. The companies producing aircraft would have remained private companies, functioning as private companies, and employing all the standard tricks - not only trying to outdo their competition by presenting a new design to beat whatever the other guys want to be the "standard" fighter, but also arguing constantly that they'll be more efficient producing their own design than re-tooling to produce someone else's (that's literally the story of the Mustang in WWII), and of course - wining and dining with their political and military connections to make sure they get the contract.
It's highly probable that there must have been a degree of standardisation given that Confed is happy to transport fighters to front-line carriers in pieces - that suggests that reassembly is a relatively simple job and that it doesn't require specialised equipment (taking up valuable storage space on a carrier) for each class of ship, which is evidence in favour of modular designs using standardised parts.
This is standard practice today, as well. It's normal for aircraft to fly under their own power onto a carrier, but that's only because it's more efficient. There is nothing whatosever to prevent the US Navy from putting together an F-18 onboard the aircraft carrier - the specialised equipment required would probably come down to a rivet gun and a blowtorch. But that doesn't mean you can put together an F-18 using F-14 parts - though we certainly do hear that some fighters share components, which is only to be expected (the WC4 novel specifically talks about this).
The second is the different service structure the Confederation Armed Forces have. As far as I can tell, every fighter belongs to the TCSF (though admittedly the carrier and ISS forces have somewhat different needs), everything corvette and upwards to the TCN, and everyone expected to land on a planet (or a Hakaga) and shoot at Kilrathi is a Marine. (It's almost like the universe wasn't created by somebody familiar with inter-service politics or something.)
Again, you seem to assume simplification where there is none. Even in your first sentence, where you state that every fighter belongs to the TCSF, you go on to mention ISS, which is, as near as we can tell, a separate service branch. And then there's all those militias we see in Privateer (with WC4 possibly implying that similar militias existed in the future Border Worlds as well, maybe even including their own capships). Besides this, however - being unified in a single service branch would not in any way alleviate the pressures of multiple requirements. Militia fighters would need to be, above all, cheap and rugged (...yet, equipped with a jump drive), while carrier fighters would need to be high-performance. And of course, you have different carrier types, with different needs - an escort carrier that's supposed to keep a backwater sector secure just won't need that wing of Excaliburs. And it won't fit that wing of Broadswords, apparently, needing instead to get its own unique variant of the Sabre...
The third is the nature of the front. This was to some extent true in the Pacific Theatre (though it certainly wasn't in Europe), but it's a much more pronounced factor in WC. Mobile forces are horrifically expensive to produce and keep supplied by comparison to garrison forces.
The nature of the front is the strongest argument against standardisation, not for it. We make something of a mistake, constantly comparing WC to the Pacific Theatre. It is comparable, in the sense that you've got lots of islands (planets) with huge space between them and carriers providing the most effective means of striking the enemy. But there's a problem - because these islands, very often, are highly populated and highly developed. It's as if the United States exploded into fifty-two pieces, with each state being a separate island, as distant from the other states as Hawaii is from the mainland. Of course, you'll have plenty of North Dakotas out there, with a negligible population and relevance to the war, but you'll also have Michigan right there in the middle of Gemini Sector, with a big chunk of your industrial capacity. You cannot merely hope that if the Kilrathi attack New Detroit, there will be a carrier somewhere nearby - not when you have about ten carriers at one time. You do need powerful local garrisons. And heck, even those North Dakotas and Arizonas will vociferously demand that they be given appropriate protection. And you need to keep them safe and happy, because they're keeping Michigan fed and supplied with raw resources. So, what you'll find is that time and again, Michigan will not wait for New York to supply them with a fresh batch of whatever the "standard" Confed fighter would be - instead, they'll produce their own aircraft locally. And then, the Confed fleet operating in the area will ask the central government a very sensible question - why must we wait for "standard" reinforcements, when we could get these local manufacturers to produce something for us much faster, with a much shorter supply line?
There's another difference, too, but I'm not sure what the effect of this one would be - in 1939, mass-produced internal combustion engines were less than fifty years old, powered flight was 35 years old and military aviation ten years younger than that. I don't know if we have any knowledge of quite how long humans have been building starfighters or fusion and jump drives for but I believe it's a couple of centuries at least.
Probably not too relevant. Seventy years down the track, internal combustion engines are more than a hundred years old... but they're no longer used by high-performance strike fighters. We don't know how many times along the way the basic technology powering Confed's fighters will have changed. We even see such a changeover taking place in WC4, with the Dragon using a totally new type of engine.
