Miles City Airport or Frank Wiley Field is a city-owned airport two miles northwest of Miles City, in Custer County, Montana, United States. The airport was served by one airline, subsidized by the Essential Air Service program. EAS subsidies ended on July 15, 2013 due to subsidy per passenger exceeding $1000, leaving Miles City without scheduled air service. Federal Aviation Administration records say the airport had 264 passenger boardings (enplanements) in calendar year 2008, 891 in 2009 and 1,033 in 2010. The National Plan of Integrated Airport Systems for 2011–2015 called it a general aviation airport (the commercial service category requires 2,500 enplanements per year). Scheduled air service temporarily ceased on March 8, 2008, when Big Sky Airlines ended operations in bankruptcy. Great Lakes Airlines was given USDOT approval to take over Essential Air Service (EAS) and flights began in 2009. From 2011 to 2013, service had been provided under EAS contract by Silver Airways (formerly Gulfstream International Airlines). Facilities Frank Wiley Field covers at an elevation of above sea level. It has two asphalt runways: 4/22 is and 13/31 is . In 2009, the airport had 11,200 aircraft operations, average 30 per day: 71% general aviation and 29% air taxi. 20 aircraft were then based at this airport: 90% single-engine and 10% multi-engine. Historical airline service The first known commercial air service to Miles City was provided by Mamer Air Transport in 1930. Mamer used Ford trimotor aircraft on a route between Spokane and Minneapolis/St. Paul making multiple stops. Northwest Airlines then served Miles City as one of multiple stops along the carrier's mainline route between Seattle and Chicago from the early 1930's until 1954. The mainline route was extended eastward to New York and Washington D.C. by 1950. Northwest flew Lockheed Model 10 Electra followed by Douglas DC-3 aircraft for its service to Miles City. Frontier Airlines (1950-1986) served the airport from 1954 until 1980 with flights to Billings and Bismarck. Some flights to Billings would continue onto Salt Lake City via multiple stops. Douglas DC-3 prop and Convair 580 turboprop aircraft were used. Combs Aviation also provided service to Miles City from 1968 through 1970 with Aero Commander 500 twin prop aircraft on behalf of Frontier via a contract agreement, and for a period in 1970, Frontier contracted all of its Miles City service to Combs. Combs then ended their contract service and Frontier returned in 1971