When planning your trip from Charlotte Douglas International Airport, one of the most common questions travelers ask is: What Terminal Is Frontier Airlines at CLT? If you’re flying with Frontier, you’ll find that the airline operates out of the Main Terminal at Charlotte Douglas International Airport (CLT). Since CLT is designed with one large terminal building that connects to multiple concourses, it makes navigating much easier for passengers. Frontier Airlines typically uses Concourse A, where you’ll find check-in counters, security checkpoints, and boarding gates dedicated to the airline.