An hour is tight but generally sufficient for a domestic-to-domestic connection at Hartsfield-Jackson Atlanta International Airport (ATL), especially if you are flying with Delta Air Lines. ATL is designed for efficiency; all seven concourses (T, A, B, C, D, E, and F) are connected by the underground Plane Train, which runs every two minutes and can get you from one end of the airport to the other in about 15 minutes. If your first flight is on time, an hour gives you roughly 20–30 minutes to move between gates before boarding for your next flight begins. However, if you are connecting from an international flight, an hour is absolutely not enough, as you must clear customs, collect your bags, and re-clear security, which typically requires a minimum of 2.5 hours. For domestic travel, as long as you don't stop for a sit-down meal, the "one-hour ATL connection" is a standard and usually successful part of the travel experience.