Taxiing past the Pinwheel helicopter (see photo 678360) at Van Nuys. This airport was used by the USAF until 1990. The old Mitchell was one of a 1000-aircraft batch from fiscal year 1944. The tail number system requires the first digit of the full serial to be omitted. When in 1954 someone observed that 1940s and 1950s planes with the same tail numbers were in active service, this was curiously addressed not by simply adding the 'decade digit', but by introducing a 0 (not O) prefix for older aircraft. See the article in our AirHistory Magazine section. Photo by: Ralph Crane / Life