Nicely done solaero. It's looking good.
I have some comments/suggestions, if I may though:
I like this as a cover page. It's got a good dramatic photo - nicely set-off by the cream(?) background - and the curves go with the aeroplane theme. It's also not too fussy. (It's very easy to put too much stuff on the page and that sometimes spoils things, but that hasn't happened here.) My only issue would be the mismatched formatting on the "highlights" but I assume you'll be clearing that up nearer the end of the project.
Inside Front Cover
A nice IFC this. A good dramatic photo of the instruments, the curve motif is continued from the cover, and the inverted-colour logo is a nice touch too. Also, nice use of shadows to give things an extra bit of interest (but see comment for page 3 below).
Nice font choice. If you don't need something fancy then just go with something that can easily be read. The reader will thank you for it (but probably not to your face). My one concern would be the gradient-filled box. I'm having flash-backs of 1990's instruction manuals that came in lever-arch folders, but maybe that's just me.
Also, a question: Is there a reason why the shadow of the curve at the top of the page is lighter than most of the other shadows (including the same place on other pages)? I only ask as I prefer the lighter shadow and think it should be used elsewhere. That's just my opinion of course. (Master pages come in very handy to keep things consistent across the document.)
One tiny extra issue I have is with the page number going over the line. It might look better if you put a gap in the line (and shadow) so the number has somewhere to "sit inside" rather than overlapping. (Also, if this is going to be a two-sided document you'll need to move the even-numbered page numbers to the left of the page. Master pages can help with this too.)
Not much to say about this page really (and that's just because there's not much to see rather than there being anything wrong with it). I don't know if the use of red for some text has any specific meaning but it does seem to help to break the text up.
I really like those charts. If I was you I'd keep using Numbers and not bother looking for other ways of generating them. (I'm going to go off when I've finished writing this and see what I can use to make similar graphs for future use.) One slight issue I have is that they're 3D with no shadows when the rest of the graphics are flat but with shadows. Maybe that's just me though, and maybe you can't (or shouldn't) do anything about it. It's probably not a real problem.
The main issue I have with this page is the use of Courier (or a similar font). For me, unless you specifically need to make something look typewritten, you should use something else. It just looks odd being next to the fancy 3D charts.
As a work in progress this is looking great so far. (Most of my comments above are minor quibbles.) It's a shame you've got to sanitize it so much but that's expected when there's sensitive information.
When this is finished you should really think about getting it added to the Success Stories pages on the Scribus Wiki. It would be a very welcome and interesting addition.
Good luck with the rest of the publication and please add more examples if you can. I'm sure a lot of people will find them very useful for inspiration.