Northwest Orient Airlines Flight 2501 was a DC-4 propliner operating its daily transcontinental service between New York City and Seattle when it disappeared on the night of June 23, 1950. The flight was carrying 55 passengers and three crew members; the loss of all 58 on board made it the worst commercial airliner accident in American history at the time.
The aircraft was approximately 3,500 feet (1,100 m) over Lake Michigan, 18 miles (29 km) NNW of Benton Harbor, Michigan when it vanished from radar screens after requesting a descent to 2,500 feet (760 m). A widespread search was commenced including using sonar and dragging the bottom of Lake Michigan with trawlers, but to no avail. Considerable light debris, upholstery, and human body fragments were found floating on the surface, but divers were unable to locate the plane's wreckage