Simmons Airlines was a regional airline in the United States. It was the predecessor to American Eagle Airlines. Its headquarters were originally near Marquette, Michigan, at the Marquette County Airport in Negaunee Township, and were eventually moved to the Near North Side of Chicago, Illinois.

Republic Airlines was an airline in the United States that operated from 1979 until it merged with Northwest Airlines in 1986. Republic was formed by the merger of North Central Airlines and Southern Airways on July 1, 1979. Their headquarters were at Minneapolis–Saint Paul International Airport, in what is now Fort Snelling in unincorporated Hennepin County, Minnesota. The former headquarters is now Delta Air Lines Building C.