Beginning in the 1980s , and later for much of the 1990s , BWI was a major hub for Piedmont Airlines and successor US Airways , but that airline 's financial difficulties in the wake of the dot-com bust , the September 11 attacks , and intense low fare competition forced it to significantly reduce its presence at the airport .
Beginning in the 1980s and for much of the 1990s , BWI was a major hub for Piedmont Airlines and US Airways .