I feel I should know this one...

But up till now I've never needed to know.
How does one get 3rd party aircraft in campaigns? I have an absolute fleet of British bombers I would like to use and I can't for the life of my figure it out and all I can find trawling the forums is that once people figure it out they don't say how they just say "all sorted now!"
So, help!
Please.
How does one get 3rd party aircraft in campaigns? I have an absolute fleet of British bombers I would like to use and I can't for the life of my figure it out and all I can find trawling the forums is that once people figure it out they don't say how they just say "all sorted now!"
So, help!
Please.
