What Terminal is Frontier Airlines at MCO? A busy hub, Orlando International Airport (MCO) is renowned for its effective layout and variety of airlines that offer flights to locations worldwide. If you’re flying with Frontier Airlines, being familiar with your terminal in advance might help you save time and improve the quality of your trip. Passengers may easily reach Frontier Airlines’ check-in counters, gates, and various services to improve their trip from Terminal A to MCO, where the airline operates.