Spirit Airlines Boston Terminal When you are prepared for the check-in procedure, flying with Spirit Airlines out of Boston Logan International Airport (BOS) may be a seamless and stress-free trip. You can follow this instructions to ensure you know exactly what to do when you reach to the airport, pick up your boarding card, and proceed to security. The main base of operations for Spirit Airlines is Boston Logan's Terminal B. Once at the airport, head toward Terminal B by following the instructions. There are long-term and short-term parking lots close by if you're traveling by car. Taxis and public transit options like the MBTA Silver Line and Logan Express can also effectively bring you to the station.