What Terminal is Spirit Airlines at BOS? The main base of operations for Spirit Airlines is Boston Logan International Airport's Terminal B (BOS). This terminal is a busy center that provides travelers with a range of amenities and services. Ticketing counters, baggage claim areas, and security checks designed to guarantee a seamless travel experience are all located within Terminal B. In addition, the terminal has shopping centers, restaurants, and cozy seating places for travelers awaiting their flights.