SIAI-Marchetti S.211

The SIAI-Marchetti S.211 (later Aermacchi S-211) is a turbofan-powered military trainer aircraft designed and originally marketed by Italian aviation manufacturer SIAI-Marchetti.

SIAI-Marchetti started to develop the S-211 in 1976 as a private venture initiative, announcing its existence during the following year. In April 1981, the first prototype performed its maiden flight. The Singapore Air Force placed the first order for ten aircraft in 1983. Some 60 aircraft have been sold to air forces around the world. Following Aermacchi's purchase of SIAI-Marchetti in 1997, the former has held the production rights to the type. An extensively redesigned and modernised derivative, the Aermacchi M-345, has been developed by Alenia Aermacchi, and entered service in 2020.

In 1976, Italian aircraft company SIAI-Marchetti began work on what would become the S-211. The project was undertaken as a private venture to develop a new basic trainer aircraft. SIAI-Marchetti planned to offer the type to the company's existing customer base, consisting of various air forces around the world that operated their SF.260, a piston-engined trainer. The programme's existence was announced in Paris in 1977. Reportedly, customer interest was strong enough to justify the construction of two prototypes, the first of which flew on 10 April 1981. In 1983, the Singapore Air Force placed the first order for the S-211, for ten aircraft.

The S-211A was a slightly modified and updated variant of the S-211, was a losing contender in the United States Air Force's Joint Primary Aircraft Training System (JPATS) aircraft selection. Among the seven aircraft to enter, the Raytheon/Pilatus entry emerged as the winner, being produced as the T-6 Texan II. The S-211 team was initially partnered with American aircraft company Grumman. Following its merger with Northrop Corporation in 1994, SIAI-Marchetti worked with Northrop Grumman on the S-211A up until the selection.

In 1997, rival Italian aviation firm Aermacchi acquired SIAI-Marchetti and thereby the S-211. According to Aermacchi, the acquisition would enable significant cost savings in production following consolidation to its Venegono Inferiore facility. Aermacchi has continued to seek customers for the type. In 2004, the company announced its intention to develop an improved version of the S-211, then referred to as the S-311, later as the M-345. At the time, Aermacchi was also developing the M-346 Master, which serves as a lead-in fighter trainer. While vaguely similar to the M-211, the M-346 is considerably larger and intended to perform both the basic and advanced training syllabus, as well tactical training functions, as an alternative to single-engined turboprop-powered competitors.