 Service from Denver also included flights to Colorado Springs, Durango, Gunnison, Hayden, Montrose, and Rifle in Colorado as well as to Farmington, and Albuquerque, New Mexico, Sioux City and Waterloo, Iowa, and Cheyenne, Sheridan and Gillette in Wyoming.The airline also operated nonstop service at one point between Salt Lake City (SLC) and Aspen, Jackson Hole, Wyoming (JAC), and West Yellowstone, Montana (WYS).Essential Air Service was operated between San Francisco and Modesto (MOD) and Stockton (SCK), California in 1982.