Making in-game movies is really challenging - I mean, making it according to MS guidelines (TCRs), and user friendly. First wasn't an issue for Halo, of course
So I can't promise it will be there. Moreover, I am not allowed to tell you this details till game site will open, actually.
But. All in-game footage that were published, were made exactly like this, in-game. That doesn't mean this feature will be in released game, however.
Sorry, I can't tell you anything about downloadable content will be available first (and which planes will be in initial release also). Stay tuned. All I can say, it seems, that you wan't be disappointed in that.