During the early 1930s, Kawasaki built Salmson biplanes and engines under license,[citation needed] and also developed a number of its own designs.

Although in November 1970, Kawasaki completed Japan's first domestically designed twin turbofan military transport, the C-1, the company concentrated primarily on licensed production of derivatives of American patrol aircraft and helicopters through the 1990s.

[citation needed] On 25 February 1977, Kawasaki and German aerospace manufacturer Messerschmitt-Bölkow-Blohm (MBB) signed an agreement to cooperate on the development of a new rotorcraft; under the terms of this agreement, the two corporations merged their previously separate projects to produce twin-engined general purpose helicopters, these being the Bo 107 by MBB and the KH-7 from Kawasaki.

[7] Each company established their own final assembly lines on which they produced the rotorcraft to meet demands within their respective local markets.

[9] The final assembly line for the type was established at Kawasaki's plant in Gifu, capable of producing a maximum of two and a half aircraft per month.

[10] In addition to economic and performance consideration, the T-4's design had to incorporate political desires as well; significant emphasis had been placed upon powering it with the first all-Japanese production turbofan engine, the Ishikawajima-Harima F3-IHI-30.

[11] According to aerospace publication Flight International, it was considered plausible for the T-4 to have been a competitive product upon the global trainer aircraft market, but such opportunities were denied by a long-standing Japanese policy that forbid military export sales.

[12] On 18 September 1992, Kawasaki was appointed by the Ministry of Defense to produce the OH-1, an indigenously designed armed observation and light attack helicopter.

[15][16] Kawasaki has proposed multiple derivatives of the OH-1, including a utility variant intended to replace the JGSDF's fleet of Fuji-built Bell UH-1J Iroquois helicopters,[18] and an attack-oriented version tentatively designated as the AH-2.

[21] Kawasaki was appointed as the prime contractor for both programmes during 2001, its launch occurred almost 30 years after the previous large-scale domestic development of an aircraft in Japan.

During 2002, the company, along with AgustaWestland and Marubeni, formalised an agreement to cooperate on the AW101's production in Japan; Kawasaki began the assembly of both the CH-101 and the MCH-101 models in 2003.

[29] In the commercial aviation business, KHI has been involved in the joint international development and production of multiple large passenger aircraft.

[citation needed] The company is also involved in the joint international development and production of turbofan engines for passenger aircraft such as the V2500, the RB211/Trent, the PW4000 and the CF34.