Continental Express/ExpressJet was at one time a wholly owned subsidiary of Continental Airlines, Inc. In this previous incarnation before its divestiture various air carriers operating as Continental Express flew turboprop aircraft such as the ATR 42, ATR 72, Beechcraft 99, Beechcraft 1900C/D, Convair 580, de Havilland Canada DHC-7 Dash 7, Embraer EMB-110 Bandeirante, Embraer EMB-120 Brasilia, Fairchild F-27, Grumman Gulfstream I, NAMC YS-11 and Swearingen Metro. Continental Express/ExpressJet was formed through the merger of four separate commuter airlines that were wholly owned by Continental: Provincetown-Boston Airlines, of Hyannis, MA, Bar Harbor Airlines, of Bangor, ME, Britt Airways, of Terre Haute, IN, and Rocky Mountain Airways, of Denver, CO. As part of the consolidation of the four commuter operations, the PBA and Rocky Mountain operating certificates were retired. The Bar Harbor certificate went to Eastern Airlines for its Florida Eastern Express division. The combined company that became Continental Express/ExpressJet operated under the Britt Airways operating certificate until November 2011, at which time all ExpressJet operations became part of the Atlantic Southeast Airlines certificate. Continental Express also served Continental's Denver and Guam hubs until the early 1990s.