Frontier Airlines ATL Terminal At Hartsfield Jackson Atlanta International Airport, Frontier Airlines is based in Terminal North (Domestic Terminal) (ATL). Concourses T, A, B, C, and D make up this facility; Frontier normally operates out of Concourse T. To find out particular gate information, passengers should consult their boarding cards. The terminal has a number of amenities, such as shops, lounges, and restaurants. Self-service kiosks are another option available to Frontier travelers for check-in and baggage drop. To account for security checks and possible delays, it is best to arrive at least two hours before departure.