So no China preclearence? Absolutely a no to "codifying national base bias" in a game. And if everyone has preclearence that wt would be the same for everyone anyway, so no point in it.
I think there should be airports with US Preclearance (go through US customs in the airport before you fly to America) For example Dublin and Shannon Airports) More passengers will try to fly to those airports to go to America so they can go through customs before they even arrive in America. This could benefit to airlines who fly to America from an airport that has US Preclearance. Hope this could benefit to the game if it is added!