This aircraft was originally the sole DL-2, a Sirius with a metal fuselage built in Detroit. By April 1931 it was converted to DL-2A Altair with retractable gear, and delivered to the US Army as the Y1C-23, a fast VIP transport often flown by Ira Eaker. Initially it still wore civil reg NR8494. Here it is seen wearing Bolling Field insignia and simplified designation C-23 just behind the cowling, which should date the photo between 1933 and 1935. On some photos the Secretary of War's flag is painted on the other side. Following a gear-up landing it was rebuilt and repainted in light blue in 1935. Condemned to ground instructional airframe following another belly landing with jammed gear in April 1938. Photo from: US Air Force

'Aviator Clarence Chamberlin's plane'. Built as an L-8A Sirius in 1930. Sold to 'Dutch' Shankle and also flown by his wife, air racer Joan Fay. Converted to L-8D Altair in 1932. Sold to Louise Ashby, Chamberlin's wife, in May 1936. The Chamberlins intended to make a stratospheric transatlantic honeymoon flight for which the razorback canopy was added after August 1936. It did not happen and the aircraft was sold to the US Army Engineers Office through broker Charles Babb in 1940. The Curtiss 53 Condor in the background was also owned by Chamberlin or his wife. Photo by: Gleason Waite Romer / Miami-Dade Public Library

'Sir Charles Kingsford Smith prepares at Croydon for last long-distance flight.' Smith and Tommy Pethybridge departed for Australia on 6 November but the plane with the two men disappeared between Allahabad and Singapore. Photo from: Nationaal Archief (Netherlands)

Developed from the Sirius, the Altair was the first Lockheed aircraft with a rectractable undercarriage. Of eleven examples built, two went to the Mainichi Shinbun newspaper in Japan. J-BAMC crashed while landing at Osaka on 12 April 1937 and the pilot was killed. Photo from: ETH-Bibliothek Zürich

Owned by famed aviator Charles Kingsford Smith, VH-USB left Australia by air in October 1934 for the US. In September 1935 it was shipped on to the UK where it became G-ADUS for an attempt on the UK-Australia record. It crashed into the Gulf of Martaban, Myanmar, on November 8, 1935. An undercarriage leg washed up on Aye island but otherwise no traces of the -USB, Smithy and copilot Tommy Pethybridge were ever found.