I've got a slightly related question about airport function in regard to region design. I'm in the planning stages of a large region and have a large city which I'm going to be plopping the airport at some point. To the right, it's neighbor, is another large city. For busting demand caps and all the other functions that an airport provides, are multiple transit links sufficient or should I plan on building an airport in both cities?
More simply, can airports serve part of a whole region or are they simply limited to busting caps in individual cities alone?
In my region I'm going for a large metro design with continuity across cities, so ideally a single airport in a single city (metro area is going to be 5 or 6 clustered city tiles, mixed sizes) would be ideal.
Thanks in advance!