> It was a pretty common urban planning concept for a large city to have one airport devoted mostly or entirely to domestic flights, and one mostly or entirely for international flights.

Which, like urban highways, really doesn't make a sense in most cases if one spends a few minutes thinking about it. And especially doesn't make sense for an airport whose main traffic is connecting international and domestic flights.

Urban planners in many places in the 1950-1990 time were... special. Blindly copying bullshit that didn't make sense originally and definitely didn't make sense in their city.