United has served Midway three times in its history:
was at MDW
until the 'official' opening of O'Hare in 1962. O'Hare really
opened in 1955 (to charter airlines only). United began jet service there in 1959, and gradually moved more and more flights there over the following years. All service was finally transferred in 1962, when the O'Hare terminal complex was completed. United was the last scheduled carrier to serve MDW
during this period.
United returned to MDW
just two years later (in 1964) with Boeing 727 jets. With ORD
already showing signs of strain, the city was trying to market Midway as the ideal spot for DC9 and B727 operations. The Midway terminal was upgraded considerably and most of the major airlines returned. United was the largest carrier, with 727 and 737 flights to Washington DC, New York (LGA
), Philadelphia, Pittsburgh, Cleveland, Omaha, Minneapolis/St. Paul and Denver.
It was during this period that the 737 crashed about three miles southeast of the airport. United was the largest carrier at MDW
(again) during this era. They ended service in 1974, citing rising fuel prices. The reality was that the majority of Chicago passengers preferred O'Hare, and Midway had gained an unsafe reputation after the 737 crash. The loads on United's MDW
flights were pretty low in the early 1970s.
United started Midway service yet again in the mid-1980s with 727 flights to Los Angeles, San Francisco and Denver. These flights operated until at least 1990 - I have a diagram of MDW
from 1990 that shows United at Concourse C. I'd guess they probably retreated back to O'Hare during the first Gulf War.