What terminal is Frontier Airlines at PHL refers to the question regarding which terminal Frontier Airlines operates from at Philadelphia International Airport (PHL). The answer to What terminal is Frontier Airlines at PHL is Terminal E. This terminal is where all Frontier Airlines flights depart and arrive, offering passengers essential services such as check-in counters, security, and various amenities to ensure a smooth travel experience. If you're flying with Frontier, make sure to head to Terminal E when at PHL for all your flight-related needs.