If I could code/think worth a damn, I'd do this - vaguely speaking...joys of never getting enough sleep:
Brand-name value of airline - length of time it's been around, number of routes, number of passengers, possibly with a cost/profit thing thrown in. Cheat a little on the numbers here and there to as to favor the extreme ends of the curve - Southwest and, say, Alaska Airlines both get equal weighting initially - size of company or price advantage. Progressively start averaging things out to middle of spectrum with each rollover update to profits et al. Same as new route advantage I've read about, I guess. My crap assumption is that ultimately the long-run players and the neophytes ripping off the current 'system' would eventually balance out and have to behave economically.
Plane age/route frequency - I'm guessing vaguely it can be tied to turn time frequency, maybe? More turns - more whacks. People running huge freqs or old planes or just 50 routes experience degraded performance from their machines; value loss, profit loss, pax loss. Older means less efficient. I don't think it's be too hard to crumble in some quick - albeit painful - adjustments there.
Otherwise, this game is far too fun. Probably not explained the best - I am eclectic, for that, my apologies.
