What Airlines fly out of Concourse B in Atlanta Hartsfield-Jackson Atlanta International Airport (ATL) is a massive travel hub, and Concourse B plays a key role in its domestic flight operations. Here are the primary airlines flying out of Concourse B: Delta Air Lines: Delta is the dominant carrier at ATL, with many domestic routes departing from Concourse B. Southwest Airlines: Known for affordable fares and excellent customer service, Southwest offers frequent flights from this concourse. Spirit Airlines: Budget-friendly Spirit Airlines connects travelers to a variety of domestic destinations. Alaska Airlines: Alaska Airlines operates select domestic routes from Concourse B, primarily to West Coast destinations.