Midwest Airlines (YX) was a U.S. based airline that offered scheduled flights to a number of cities within the country. The list included Phoenix, Newark, Kansas City, Seattle and Denver among a total of 18 destinations. Midwest was headquartered in Oak Creek, Wisconsin, its other important hubs being General Mitchell International Airport, Milwaukee and Kansas City International Airport. Formerly a subsidiary of Republic Airways Holdings, Midwest ceased to exist as a separate airline post its merger with Frontier Airlines
in April, 2010.