Great Lakes Aviation goes to great lengths to get people where they need to be, even if it's far from the big city. Flying as Great Lakes Airlines, the regional carrier transports passengers to more than 60 destinations in the western and midwestern US, mainly from Denver but also from markets such as Phoenix, Kansas City, and Ontario, California. It maintains code-sharing agreements with Frontier Airlines and United Airlines. (Code-sharing enables carriers to sell tickets on one another's flights and thus extend their networks.) Great Lakes operates a fleet of about 40 turboprop aircraft, consisting mostly of 19-passenger Beechcraft 1900Ds but also including 30-passenger Embraer Brasilia 120s.