I, too, would like these both implemented. I realize it's much more work, but on the other hand it gives a great variation to gameplay; some like to play it real from day 1, while others like to see how they are making the difference in the game. You could even play 2 games at once in the same airport and still have a very different game experience.
So, maybe there should be some simple variables that limit how much an airport may grow/diminish in the game. For example a four stage limit, that ranges from 1- follows history, does not grow after 2012 (or grows like now), to 4 - all airports start at their historical size for that year, but are then totally dependant on player actions.
And when creating the game, admin could choose which limit to use for the game.
However, if it comes to only choosing one option, you could make it player-driven, but include certain larger airports that are in or close to a city and prevent them from growing too much.