Beginning in the 1980s and for much of the 1990s, BWI was a major hub for Piedmont Airlines and US Airways. Financial problems because of the dot-com bust, the September 11 attacks, and competition which lowered ticket prices caused them to be less active at the airport. Southwest Airlines' began using the airport in September 1993. Southwest is now the airport's largest carrier. It had 56.76% of the passengers carried in 2008. Southwest recently bought AirTran. Because of this, Southwest Holdings now has an average of 214 departures each day. BWI is now Southwest's 3rd largest destination. BWI has International flights to London, Mexico, Canada, and the Caribbean and domestic flights throughout the United States.