North Central Airlines Flight 290 was a regularly scheduled flight which usually originated in Houghton, Michigan, and stopped at Ironwood, Michigan, and Green Bay, Oshkosh, and Milwaukee, Wisconsin, before terminating at Chicago, Illinois.
Air Wisconsin Flight 671 was a regularly scheduled flight from Chicago, Illinois, to Appleton, Wisconsin, with a stopover at Sheboygan County Memorial Airport west of Sheboygan, Wisconsin.