Mainliner Chicago was with United Airlines 1952 - 66 as a Convair 340 registered N73118. Sold to Lake Central Airlines, it was converted to a 580 When Lake Central merged with Allegheny Airlines in 1968, it was re-registered N5840. Sold to Great Lakes Airlines as C-GDTD in 1976 and rebranded Air Ontario in 1981. The aircraft was sold in 1987 as OO-VGH, operated by European Air Transport for DHL cargo services. Retired in 1991, it was scrapped at Brussels by 1994.