Col Wolf,
Lot's of airfile entries interact with each other, so you won't find a simple value to adjust.
Record 1205 Horizontal Stab has an entry for incidence. If this is negative, it's often being used to try to centre trim in an a/c that's purposely been made "unstable" (C of G - wise) to aid maneuvrability.
Within Section 1101 Primary Aerodynamics the following entries adjust trim settings:
Cmo Pitch moment Coeff at AoA 0 (as Allen suggested) - I think this primarily fine tunes the fuselage incidence at cruise
but further down (same section Pitch) we also have Cm -dt Pitch Moment. Most a/c have -0.5 or -0.6, but occasionally you have larger values, particularly if the main wing incidence is set > 1 deg (section 1204, incidence).
The AI in particular in CFS 2 struggle to remain in formation if the airfile wing incidence is > 1 degree, so often the real value doesn't help with AI performance in the sim.
Remember CFS 2 is a Combat sim, & not as sophisticated a model as the later MS flight sims. That said, later MS flight sims are all meant to be optimised for Player a/c flight experience, & not formations that include wingmen, or AI only flights.
My main point is there are lot's of interacting records within the airfile - trial & error is your friend to seek what you need.
You might take a look at Aircraft Airfile Manager v2.2. Although made with FSX in mind, it's record visualisations & explanations are somewhat more comprehensive than those notes with AirEd.
Or just accept the set up as you find it & go shoot something down instead...
