About 8 miles or 12 kilometres.
Atlanta is currently listed as the busiest in terms of take offs and landings. Whether or not it is the "main" US airport depends on what criteria you are using. Certainly JFK, LAX, ORD, DCA and IAD...
Terminal 2 is a new terminal in Dublin Airport and will be used by Aerlingus, Delta, Continental, American Airlines, US Airways & Etihad Airlines.
There is one airport called Banjul International
Catholicism.