United Airlines began serving Casper in 1984 with nonstop Boeing 727-100, 727-200, and 737-200 jet flights to its Denver hub. In 1987, United mainline jets were replaced with United Express service flown by Aspen Airways (1987–1990) with Convair 580 turboprops and British Aerospace BAe 146-100 jet aircraft, then by Mesa Airlines (1990–1998) with Beechcraft 1900C, de Havilland Canada DHC-8 Dash 8 and Embraer EMB-120 Brasilia aircraft. Air Wisconsin then provided United Express service (1998–2002) with Dornier 328 propjets followed by Great Lakes Airlines (2001–2003) using Beechcraft 1900D aircraft. Great Lakes lost their designation as United Express in 2002 but continued to provide flights to Denver under its own branding. SkyWest Airlines then resumed United Express service in 2003 using Embraer 120 turboprops and later upgrading with Canadair CRJ-200 jets.