Great Lakes Airlines is a big, little US regional airline flying a big fleet of small aircraft to many domestic destinations.

Great Lakes Airlines is headquartered in Cheyenne, Wyoming and has bases at Denver, Kansas City, Phoenix Sky Harbor, Billings Logan International, LA/Ontario International, Milwaukee, and Albuquerque.
Flights on Great Lakes Airlines
Great Lakes Airlines operate a fleet of 35 aircraft including 6 Embraer EMB 120 Brasilias and 29 Beechcraft 1900D's , this makes them the world's largest operator of this aircraft type. The airline uses Government subsidies as part of the Essential Air Services programme to connect up to 60 rural communities which otherwise may not have regular air services plus codeshare agreements with larger carriers.
All scheduled flights are operated under the Great Lakes Airlines marketing identity in conjunction with codeshare agreements with United Airlines and Frontier Airlines at their Denver, Phoenix, and Billings hubs. Codeshare agreement with only United at their

Kansas City and Ontario hubs; and only Frontier at their Albuquerque hub. The company also operates a hub in Milwaukee.
Regional US Flights with Great Lakes Airlines