Kellett helicopter with twin intermeshing rotors. This prototype first flown 7 August 1944. One XR-8 and one XR-8A built. Programme cancelled by US Army in 1946, but at least one of the helicopters was still being flown in 1947. Photo from: Wright State University

Light aircraft by the innovative Hall Aluminum Aircraft Corporation. Only one mainwheel but note the extensive strutting for the outriggers. Did the strange wing slats slide back? Also had unusual steering system hanging from the roof. Photo date given as 1 November 1936, but Charles Ward Hall was killed crashing this aircraft into a tree on 21 August 1936. Photo by: Rudy Arnold / Smithsonian Institution

Although wearing a Tactical Air Command badge on the fin, the aircraft was actually operated by the Pennsylvania air national guard. This is actually an EC-130E(CS), or Coronet Solo, aircraft. The River Rider program did not come into existence until 1991, and the aircraft were modified with notably different electronics. This aircraft was assigned to the 193rd Special Operations Sq., 193rd Tactical Electronic Warfare Group, Pennsylvannia ANG, which was operationally attached to the Tactical Air Command at the time, hence the TAC badge on the tail. The aircraft was first modified for the Comfy Levi mission (which later became Senior Scout) before modification for the Coronet Solo mission.

The civil variant of the G & A XR-9, with side-by-side seats. The sole example has a manufacture date of 15-Mar-1946 and was shown at the National Aircraft Show in Cleveland in November 1946, by then sporting Firestone titles as G & A had become Firestone Aircraft. Photo from: Vertical Flight Society

The US Army's GAX programme was an early attempt at an armoured ground attack aircraft, to be fitted with a 37-mm cannon firing through the propeller hub. Built by the Aeromarine Plane and Motor Company of Keyport, New Jersey, the PG-1 was, not surprisingly, a poor performer and unpopular with Army test pilots. The first of three machines delivered to the USAAS, 64245 is seen wearing McCook Field project number P-240.

A February 1932 article in Time magazine makes clear the original Air Ferries company in the San Francisco Bay area only operated until the fall of 1931. Walter Varney gave it another try, flying between the 'landing button' at Pier 5 in San Francisco and the Bay Airdrome in Alameda. The 'big' Loening C-2 was replaced by the Sikorsky S-39, a single-engined derivative of the S-38. The fare was reduced to $1, but the air service ceased again in August 1933, several years before the opening of the San Francisco-Oakland Bay Bridge which is blamed for its demise. Photo from: San Diego Air & Space Museum

Built for transatlantic flight by Laura Ingalls but Amelia Earhart became the first female to solo across the Atlantic instead in 1932. Ingalls then flew the aircraft around South America and over the Andes in 1934. It was NR974Y then and had the cabin windows faired over. It passed to other operators and is reported destroyed in a wind storm in Nevada in 1942. Ingalls, meanwhile, had developed outspoken Nazi sympathies and was arrested as a German agent. Photo from: Browning Studio / New-York Historical Society

Any self-respecting US millionaire owned an 'air yacht', but the C-2 Air Yacht was sometimes used as an airliner, Western Air Express flying it between LA and Catalina Island. This service was taken over by Wilmington-Catalina Airline in June 1931 - see photo 356988. Photo from: San Diego Air & Space Museum

last known operator was P.C.D.Corp, McAllen, TX

The first XR-5 prototype, 43-28236, suffered significant damage following a tail rotor failure on 12 October 1943. Test flying resumed with the second XR-5, 43-28237, in the last week of November 1943. 43-28327 assigned to 4020th Base Unit, Wright Field, Dayton, Ohio. It fatally crashed at Alachua Field, Gainsville, Florida on 2 December 1944, when welds in the main rotor failed. Photo by: Rudy Arnold / Smithsonian Institution

The Sikorsky R-5 (S-48) was an improved R-4 (VS-316), the first of five XR-5s flying on 18 August 1943. The first 26 out of 60 production R-5As were given the YR-5A designation and 43-46604 must have been one of nine YR-5As delivered before the end of WWII. The design was enlarged and further improved in 1946 as the R-5F (S-51). Redesignated as an H-5A in 1948, 43-46604 was involved in an accident in New Mexico on 20 September 1949. Photo from: Wright State University

With the old Rockwell logo on the fuselage. Any help on the location is appreciated. Photo via G.Bouma

Any help on the location is appreciated.

R-6A helicopter transferred to the US Navy. VX-3 was tasked with evaluating helicopters between July 1946 and April 1948, formed at NAS New York and moving to NAS Lakehurst. Photo by: Edgar Deigan

14 Pinto aircraft were delivered to training squadron BTG-1 at Naval Auxiliary Air Station Saufley Field, Florida from July 1958, to test the feasibility of an all-jet training syllabus. Performance was poor and the little jets were phased out in 1960. This airframe presumably survives as the Ezell EJ-1, N4229.

Sea trials for a civilian Hiller 1100 prototype, sometimes reported as an OH-5A. Photo from: Nationaal Archief (Netherlands)

The first Model 205 stretched Hueys were seven YUH-1D prototypes, 60-6028 through 6034. Photo from: Wright State University

Built in 1929 as a Vega 2. To Canadian-American Airlines for use on Minneapolis to Winnipeg route. Sold to Hanford Tri-State Airline in 1931, which became Hanford Airlines in 1936 and Mid-Continent Airlines in 1938. Air mail route 26 was Kansas City to Minneapolis. The Vega ended up with Lineas Aereas Mineras, registered XA-DEC. Last seen derelict on a beach near Ensenada, Mexico in the late 1940s.

The Hiller 1100 prototype, N81005 (c/n 1) first flew on on 21 January 1963. The type competed in the US Army's Light Observation Helicopter (LOH) competition and 62-4206 was the first YOH-5A. Although the serial is correct, it was found at some point that 62-4201 had been assigned twice, to a C-140 and a Bell YOH-4, and thus a few serials were changed, 4206 becoming 4207 in a paper exercise. This airframe was also NASA 530. Photo from: Wright State University