United Airlines Flight 553, a Boeing 737, crashes after aborting its landing attempt at Chicago Midway International Airport, killing 45. This is the first-ever loss of a Boeing 737.

United Air Lines Flight 553 was a scheduled domestic flight from Washington National Airport to Omaha, Nebraska, via Chicago Midway International Airport. On December 8, 1972, the Boeing 737-222 serving the flight, City of Lincoln registration N9031U, crashed while approaching Midway Airport. The probable cause of the crash was concluded to be the captain's failure to properly manage the flight.

The Boeing 737 is an American narrow-body aircraft produced by Boeing at its Renton factory in Washington. Developed to supplement the Boeing 727 on short and thin routes, the twinjet retained the 707 fuselage width and six abreast seating but with two underwing Pratt & Whitney JT8D low-bypass turbofan engines. Envisioned in 1964, the initial 737-100 made its first flight in April 1967 and entered service in February 1968 with Lufthansa. The lengthened 737-200 entered service in April 1968, and evolved through four generations, offering several variants for 85 to 215 passengers.

Chicago Midway International Airport is a major commercial airport on the southwest side of Chicago, Illinois, located approximately 12 miles (19 km) from the city's Loop business district, and divided between the city's Clearing and Garfield Ridge communities. Established in 1927, Midway served as Chicago's primary airport until the opening of O'Hare International Airport in 1944. Midway is one of the busiest airports in the nation and the second-busiest airport in both the Chicago metropolitan area and the state of Illinois, serving 22,050,489 passengers in 2023.