[Jukka Juutinen]

I don´t know about the 262 situation, but AFAIk e.g. on the Bf 109 there exist extremely detailed production drawings. And e.g. for the Ar 234 there is the very interesting detail drawing sheet in the 234 book by AJ Press.

There is another source so poorly used so far: production line photos. I have seen some old Luftfahrt journals which included many such photos (e.g. a very interesting shot showing many details of Ha 139 wing spar construction). And such photos on US aircraft seem reasonably common (see e.g. American Aircraft Production in WW two by Joshua Stoff).

The difference (naval/aircraft books) also applies to text. E.g. the Anatomy of the Ship series has extensive structural descriptions, in some cases the machinery description having several pages alone.

So, I don´t buy the lack of sources theory, at least in general. I think the main reason is the non-technical background of aviation authors. While many have e.g. pilot background, it isn´t enough.