"Air Age Debut: Introducing new features of speed, comfort and operating efficiency to air travelers is United Airlines' four-engined, five-mile-a-minute Mainliner 300 (Douglas DC-6), accommodating up to 52-56 passengers plus 6000 pounds of cargo. Airport scenes such as this emphasize the immensity of the new luxury airliners with their 117 ½ foot wing span and 100 ½ foot length." (United Air Lines Photograph)

"New Luxury Airliner: New giant of the airways, United Air Lines' five-mile-a-minute, four-engine Mainliner 300 has been making cross-country operational and training flights and visiting cities along United's coast-to-coast and Pacific Coast route prior to going into scheduled service about April 1. The Douglas-built luxury liner, commonly referred to as the DC-6, is capable of coast-to-coast flights in 8 ½ hours and will carry 52 to 56 passengers plus 5,400 pounds of cargo. United is taking delivery of 35 of these new postwar planes." (United Air Lines Photograph No. 241)

Delivered to United Airlines as NX37503 in November 1946. To Mars Aviation on 23 June 1968 and then BMR Aviation in September that year. Registration cancelled on 14 June 1976 and then to an unknown owner in Oklahoma City, OK. Further registration changes noted in January 1977 to the same owner and then reported as scrapped. (United Airlines Photograph No. 308 - 1947)

Taken at Chicago Municipal Airport for a flight to Kansas City. Registered to United Airlines/National Air Transport on 3 June 1931. Replaced by the Boeing 247 it was sold to TACA, Honduras on 15 July 1935. Re-registered to TACA Nicaragua as AN-AAK24 January 1942. Sold to an unknown owner in Mexico in January 1946 as XA-FON. The aircraft was later operated by Servicios Aereos de Chiapas and was written off after a double engine failure resulted in a non-fatal crash on a flight from Veracruz-Las Bajadas Airport with four POB for Minatitlan/Coatzacoalco Airport, Mexico. (United Airlines Photo)

Delivered to UAL on 1 December 1936. Leased to Eastern Airlines on 1 January 1938 with Fin No. 072. It was destroyed in a hangar fire on the 12 January 1941 at Salt Lake Municipal Airport, Utah. (United Airlines Photograph)

This Caravelle travelled back to Europe and served as PH-TRY before returning back to the US as N777VV. Note N7511A Boeing 707-123 (17638) "Flagship New Jersey" of American Airlines in the distance, about to depart. The tail of N37587 Douglas DC-6B (45492) "Mainliner Toledo" of United to the left.

Taxiing for departure on runway 27R at CMH.

Seen leaving the gate at DEN. it carries a Mainliner name under the cockpit but I've been unable to discover what it was.

Delivered to United Airlines November 24, 1968, N9037U would leave the fleet fairly quickly in April 1973. Sold to Frontier Airlines (N7383F), the aircraft would go on to fly into the next century. Moving to Africa in 1995, it was last with Aero Africa as 3D-AAJ from 2004. Retired in 2007, the aircraft was stored at Gateway International Airport (now Polokwane International Airport) in Pietersburg (now Polokwane), South Africa. It was broken up there in 2014.

Seen here when brand new taxiing for departure from CMH on runway 9R.

Holding for runway 28L at Port Columbus.

To the USAAC as 42-68369.

Photographer: Not known.

About to land on runway 28L at CMH

from my collection, photographer unknown, the DC-6 was delivered to United Air Lines in 1956 and operated with them until late 1966, purchased by Fred Olsen Air Transport and operated for SAS Cargo as LN-FOL. Took part in the Biafran airlift for Joint Church Aid between 11/69 and 2/70. Sold to Iscargo as TF-IUB in 1974 and wfu and b/u in 1980, nose section kept being preserved by the Icelandic Aviation Historical Society Akureyri

Wears 'Flight Research' titles. Used to test radio equipment and safety features. Later painted white and red. Ended up in Mexico. Photo by: Carl Mydans / Life

In flight over San Francisco. The 1939-1940 Golden Gate International Expo is under construction on Treasure Island, with the Pan Am flying boat terminal on the right side. As N16070 this DC-3 is preserved in the Evergreen museum in McMinnville, Oregon. Photo by: Carl Mydans / Life