Early history   In 1939 the Four Wheel Drive Auto Company (FWD), a major manufacturer of four-wheel transmissions and heavy-duty trucks based in Clintonville, Wisconsin, opened a flight department and traded a company truck for a Waco biplane for their company's use. In 1944 company executives decided to start an airline. In 1946 airline service was started between six Wisconsin cities. This led the company to purchase two Cessna UC-78 Bobcats. Soon after this the airline purchased three Lockheed Electra 10As. They increased service to 19 cities, and (with increasing revenues) purchased three more Electra 10As, and then 6 DC-3s.   Post Wisconsin Central history   In 1952, the airline moved its headquarters from Wisconsin to Minneapolis, Minnesota, and its name was changed to North Central Airlines. Soon after this the airline ran into some financial troubles when President Francis Higgins left, making Hal Carr the president, who quickly got the company out of debt and made it more reliable. Over time, the company expanded its fleet to 32 DC-3s.    

Revenue passenger traffic, in millions of passenger-miles (scheduled flights only)

In the late 1950s the airline began to outgrow its fleet of DC-3s and bought five Convair 340s from Continental Airlines, the first entering service in 1959. In 1960 North Central hit the one million passenger mark and had flights to 90 cities (and somewhat fewer airports). The airline added routes to Canada.  

North Central DC-9-31 at Toronto's Malton Airport in 1971 The airline even worked with the U.S. government to aid troubled airlines in South America. As the airline grew it needed larger planes; the first of five Douglas DC-9-31s entered service in 1967. The Convair 340s were converted from piston power to turboprop Convair 580s. The airline bought more DC-9s and operated a total of 29 Convairs.   In 1969 North Central Airlines moved its administrative and operational headquarters to a building on the south side of Minneapolis-St. Paul International Airport; as of 2009 the building was the Building C Maintenance and Administrative Facility of Northwest Airlines.   The CAB classified North Central as a "local service carrier," operating a combination of turboprop and jet aircraft to serve cities within one region of the United States and helping feed passengers to larger "trunk airlines" that served cities nationwide. North Central did eventually fly to more distant cities outside of the Midwest, such as Washington, D.C.-National, New York-LaGuardia, Boston, Denver, and Tucson.    

Merger  

Republic retained  "Herman the duck" and  North Central's colors Following North Central's success, it moved to buy Atlanta-based Southern Airways. The two airlines formed Republic Airlines in July 1979, the first merger following airline deregulation. Republic soon targeted San Francisco-based Hughes Airwest for acquisition, and the deal was finalized in October 1980 for $38.5 million. Saddled with debt from two acquisitions and new aircraft, the airline struggled in the early 1980s, and even introduced a human mascot version of Herman the Duck.   Republic kept North Central's hubs at Minneapolis and Detroit, and Southern's hub at Memphis, Tennessee. But within a few years it closed down Hughes' hub at Sky Harbor in Phoenix; reduced North Central's sizeable station at O'Hare in Chicago; and reduced Southern's sizeable station at Hartsfield in Atlanta. Republic also quickly downsized North Central's operations to and among smaller airports in the upper Midwest, concentrating its fleet at the Minneapolis and Detroit hubs.   In 1986, Republic merged with Northwest Orient Airlines, which was also headquartered at Minneapolis and had a large operation at Detroit, which ended the legacy of Wisconsin Central and North Central. Following the merger, the new airline became Northwest Airlines, which merged into Delta Airlines in 2010.