Gentlemen, the simplest expedient is to retain F3 mode but remove the ability fire guns in it.
Easiest way for HTC to implement it. I agree.
However, I think the thought process should go deeper than that. First, I agree with BnZ's statement: Eliminate the ability to fire in F3 view. Then, I think HTC could set up a flow chart of qualifications for which aircraft can have it based on XYZ criteria. I suggest forgetting the classification of the aircraft as a starting point, case in point being the 2 Mossi versions: same exact aircraft, same exact real world view capabilities, yet 2 very different Aces High view abilities. The role, abilities, speed, ordnance, early way vs late war, color, altitude, blah blah blah, etc, should not be an issue, imo. What the people inside that aircarft could actually typically should determine if it has F3 capability or not.
I think it should be a plane by plane examination and the ability should be based on the position of the eyes within the aircraft.