The starting point for reasonably priced travel is the Spirit Airlines BWI Terminal at Baltimore/Washington International Thurgood Marshall Airport (BWI). Situated in Concourse D, it provides a simple, uncomplicated experience to get you to your destination. In addition to adjacent dining and shopping options to kill time before your trip, expect welcoming staff who are ready to help with check-in and boarding. Spirit Airlines offers simple, low-cost travel from BWI's state-of-the-art terminal.