Pitts produced limited numbers of aircraft during the 1940s and 1950s. The Pitts Special became the standard by which all other aerobatic aircraft were judged. After a number of homebuilt aircraft were produced from rough hand-drawn plans produced by Pitts, more professionally drawn plans went on sale in 1962. While many homebuilt aircraft were built in the 1960s, earning the S1 a reputation as an excellent aerobatic aircraft, Pitts worked on the design of a two-seat aerobatic trainer version, the S-2, which first flew in 1967 and gained its type certificate in 1971. Factory-built aircraft produced by the Aerotek company at Afton, Wyoming were joined in production by the single-seat S-1S in 1973.