- Boston Logan International Airport's Terminal A is where Frontier Airlines is based (BOS). With a number of amenities to make your trip comfortable, the Frontier Airlines BOS Terminal is simple to use. You'll find everything you need prior to your journey, including dining options and seating areas. Whether you are traveling for work or pleasure, Terminal A offers a practical and effective area for all of your requirements. Look for clear directions to Frontier's check-in counters and gates on the airport signs.