What Terminal is Sun Country Airlines at BWI? Based in Baltimore/Washington International Thurgood Marshall Airport (BWI), more precisely in Terminal E, is Sun Country Airlines. Many amenities are available at this terminal, which is primarily used for international flights, to enhance the guest experience. Sun Country flight attendants have a selection of dining and shopping alternatives after clearing security and checking in at the proper stations. When your departure date draws near, it's a good idea to arrive early and verify any updates on your flight or terminal information. For more information visit-......See More