Spirit Airlines BWI Terminal offers inexpensive flights and is mostly based out of Concourse D at BWI Terminal. Because of the airline’s particular luggage restrictions, which include additional fees for checked and carry-on bags, it’s imperative to arrive early in order to efficiently handle check-in and security. To save time, think about printing your boarding card in advance of your arrival and checking in online. While you wait for your flight, explore Concourse D’s eating options and amenities. Understanding Spirit Airlines’ operating processes will make your journey from Baltimore/Washington International Thurgood Marshall Airport go more smoothly.