Thanks Sokol1,
I'm very much a novice at using the builder, certainly not a code wielding person, so was a bit baffled by the text you listed, but then I realised,... that's the .mis file as you mention at the bottom!
Sorry, as I say, I'm very much a novice, I made a few simple missions on IL2 (PF/46) in the pacific but that was all.
Anyway, I had a look at my test file and yep, no aircraft etc., so cleared all the text using wordpad, put your text in, saved, loaded and it worked fine.
I was still having problems though in actually using the builder interface, if I tried to create an 'aircraft' object it gave me a list of airfield items, hey even if I tried to select a herd of cows it just gave me runways and the like.
Just as a possibility, I used the verify local content function on Steam, which then downloaded some files (perhaps due to the fact that I had the EXCELLENT Redux campaign installed?) and then when I went in to the builder as before, I was able to create aircraft objects, and more importantly, when I tested it, there was my Spit, and a JU87 where I'd requested it!
So, all appears ok for now, I'll be back though if I struggle again!
Thanks for the insight into the .mis file, much appreciated.
Chief WH