Frontier Airlines ATL Terminal operates out of Hartsfield-Jackson Atlanta International Airport (ATL)'s Domestic North Terminal, mainly using gates in Concourses D and E. Travelers can access essential services like check-in counters, baggage claim, security, and ticketing within this terminal. Travelers can check in in three different ways: online via the airline's website, at self-service kiosks, or at airport counters. It's crucial to arrive at least 90 minutes in advance of domestic flights to guarantee that everything goes according to plan.