Also, do not forget to consider that New York City has three airports serving the area (JFK, EWR, and LGA). Combined, these might be bigger than ATL (not sure about that though). Southern California has a ton of other airports besides LAX, such as burbank, orange county, long beach, etc. Chicago has Midway as a backup. In Atlanta, unless you're in an executive jet there is no other airport within one hour of the city by car (except perhaps the tiny Macon airport, but that's a stretch).