What Terminal is Frontier Airlines at ATL , Terminal S is home to Frontier Airlines. This terminal houses the passenger check-in desks and self-service kiosks for Frontier. It is recommended that you arrive early to allow enough time for security clearance and check-in. Terminal S offers a variety of services, such as shops, lounges, and food and beverage options, to enhance your travel experience. For up-to-date flight and gate information, keep an eye on the airport's digital monitors. The first step to a trouble-free Frontier Airlines journey is locating your terminal!