While US Airways made immense cuts in service during the early 21st century, other carriers began to play a more dominant role at PIT. The airport's operator, the Allegheny County Airport Authority, has attempted to attract new service to the airport, particularly low-cost and international carriers. AirTran Airways, which had trouble competing in Pittsburgh after beginning service in 2000, was able to expand Pittsburgh offerings after the US Airways cuts. In 2003, USA3000 Airlines began service to Florida and subsequently expanded to include international destinations in the Caribbean. Southwest Airlines began service to Pittsburgh in May 2005 and broke US Airways's monopolies on Tampa, Phoenix, Las Vegas, and Philadelphia, and brought more competition to the Chicago and Orlando markets. As of March 2017, Southwest served 17 destinations from the airport, more than any other incumbent carrier. JetBlue Airways began service on June 30, 2006, with flights to Boston-Logan and New York-Kennedy, thus in turn breaking US Airways' monopoly on Boston and added more competition to the New York market. Myrtle Beach Direct Air began service in March 2007. Combined increases in competition and diversification of carriers at the airport led to a decline in average airfares by roughly 30%, lowering notoriously high fares once commonplace for the airport. In May 2015, it was announced that Southwest Airlines was looking into expanding in Pittsburgh and possibly designating it as a focus city. In September 2015, Toronto based regional carrier Porter Airlines began daily non-stop service from Pittsburgh to Billy Bishop Toronto City Airport, however the route was discontinued in September 2017.