Although overshadowed by other designs such as the C-47, the Lockheed C-60 Lodestar filled a vital medium range gap in the transport fleets of the USAAF and numerous other foreign operators. The Lodestar was a direct development of the Super Electra airliner (which had also served as the basis for the venerable Hudson patrol bomber) but with a longer fuselage and increased weights which could allow it to carry up to 18 fully equipped troops or 22 passengers. The C-60 was largely unsung during World War II yet served as a general transport, paratroop carrier, VIP aircraft, air ambulance, and glider tug. It was also exported to numerous foreign operators (usually former civil units supplied via Lend-Lease), most notably the RAF which had four squadrons of Lodestars for service in the Middle East but also Australia, Brazil, Canada, the Netherlands, New Zealand, and South Africa. After the war, most were returned to civil use.

The Lockheed Model 18 first flew on 21 September 1939 with export sales beginning two years later. USAAF military variants began with the C-56 with Cyclone engines, the C-57 with Twin Wasps, and the C-59 with Hornets although the major build type was the C-60 and C-60A which accounted for the grand majority of production. US Navy units were known as the R5O and came in a numer of different variants which mostly differed on their powerplants. RAF variants via Lend-Lease were known as Lodestar Mk. I or IA (C-59) and Mk. II (C-60).