Area 51 providers (including Russian providers and the IKONOS) are commercially available. These show the runway markings, base facilities, aircraft, and vehicles. When documents that mention the Nevada Test Site (NTS) and operations at Groom are declassified, mentions of Area 51 and Groom Lake are routinely redacted. One exception is a 1967 memo from CIA director Richard Helms regarding the deployment of three OXCART aircraft from Groom to Kadena Air Base to perform reconnaissance over North Vietnam. Although most mentions of OXCART's home base are redacted in this document, as is a map showing the aircraft's route from there to Okinawa, the
North American P-51 Mustang variants for the P-51 came from tests carried out at facilities such as the USAAF's "Flight Test Engineering Branch", based at Wright Field near Dayton, Ohio and, for the RAF, the Aeroplane & Armament Experimental Establishment (A&AEE), based at Boscombe Down. North American Aviation carried out their own performance tests, as did the only other manufacturer of the P-51, the Commonwealth Aircraft Corporation (CAC) of Australia. North American P-51 Mustang variants Over twenty variants of the North American P-51 Mustang fighter were produced from 1940, when it first flew, to after the Second World War, some of which were employed also