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.

K25 slide scan. Built 1952 as CV-340 CV-340 N73118 for United. Converted to CV-580 for Lake Central 1966, merged into Allegheny 1968. Great Lakes C-GDTD 1976, renamed Air Ontario 1981. EAT OO-VGH 1987, operating for DHL. Withdrawn Brussels 1991, scrapped 1994. Although operating as a freighter the aircraft had no cargo door, a fact which probably led to its early withdrawal.

Was the airline prior the name change to Air Ontario.

Became N5840 when Allegheny acquired Lake Central.

This 1952-vintage airframe was built as CV-340 "Mainliner Chicago" for United and was converted to turboprop while with Lake Central (still as N73118) in 8.66. Merged into Allegheny 8.68 becoming N5840; to Great Lakes 4.76, renamed Air Ontario 1.81. Sold as OO-VGH for EAT in 7.87 then DHL; hard landing at BRU and wfu 9.91, scrapped by 12.94