What Terminal is Spirit Airlines at IAH? With five terminals, Houston's George Bush Intercontinental Airport (IAH) is a busy hub for both local and international travelers, providing a smooth travel experience. Knowing which terminal to use is essential for a hassle-free flight with Spirit Airlines. Spirit Airlines, which operates out of Terminal A at IAH, is well-known for its broad network and affordable pricing. This terminal has quick check-in counters, contemporary amenities, and easy access to places to eat and shop.