Diamond Aircraft Industries is a manufacturer of general aviation aircraft and motor gliders, based in Wiener Neustadt, Lower Austria, Austria. It has been a subsidiary of the Chinese company Wanfeng Aviation since 2017. It is the third largest manufacturer of aircraft for the general aviation sector, and has operational facilities in both Lower Austria and Ontario, Canada, as well as further production lines operated as joint ventures in other nations, such as China.

The company was founded by Austrian aircraft designer Wolf Hoffmann in 1981, at which point it was known as Hoffmann Flugzeugbau. Its first aircraft, a motor glider initially known as the HK36 Dimona, became a commercial success and led to improved models and further types of aircraft derived from it. Following several changes in ownership and naming, the company received the name Diamond Aircraft Industries in 1998. By this point, Diamond was producing a range of light aircraft, including the Dimona, the Diamond DA20, and the in-development Diamond DA40.

In 2004, Diamond introduced its first multi-engined aircraft, the Diamond DA42 Twin Star. Demand from government operators led to the development of the Aeronautics Defense Dominator, a medium-altitude long-endurance (MALE) unmanned aerial vehicle (UAV) used for aerial surveillance. For several years, the company was developing a single-engined very light jet, the Diamond D-Jet, intended for both private and military customers. However, due to the Great Recession, development of the jet slowed and was ultimately discontinued in 2013.

In 1981, a new company, Hoffmann Flugzeugbau, was founded by aircraft designer Wolf Hoffmann in Friesach, Carinthia, Austria; it was formed with the ambition of becoming a major aircraft manufacturer for general aviation purposes. According to Michael Feinig, a future managing director of the company, the firm's leadership had recognised that there was a market for a range of modern light aircraft, and that the general aviation sector had been then dominated by mostly old designs from established manufacturers. By taking advantage of innovations in avionics and manufacturing technologies, the market could be entered by a capable competitor.

Hoffmann Flugzeugbau quickly set about the development of a suitable aircraft to launch its product range with. Accordingly, during the early 1980s, the company launched production of a two-seat all-composite motor glider, initially known as the H36 Dimona. The H36 demonstrated the company's ambition to raise both the quality and performance of such aircraft while making them available at competitive prices. The type was relatively successful, becoming the biggest-selling motor glider in Europe and, by 2004, four separate versions of the Dimona - which were marketed as the HK36 Super Dimona or Xtreme - were available for purchase.

In 1985, the company was renamed Hoffman Aircraft Limited and became a subsidiary of Simmering-Graz-Pauker AG, which resulted in the company's headquarters being relocated to Vienna. During 1987, the company reestablished its main production facility in Wiener Neustadt, Lower Austria. During the late 1980s, amid the various corporate changes in both identity and ownership, the company's management had proceeded with its work towards the goal of rapidly expanding Hoffman's product range.

In line with this mission statement, it had been decided to develop a new two-seat aircraft, the HK36R, which used the H36 Dimona as a basis. This would result in the production of the DV20 Katana, a Rotax 912-powered two-place light aircraft, which was the company's first production general aviation aircraft.

During 1991, Hoffman's parent company was renamed HOAC AG and was purchased by the Dries Family.