In 1918, a French military mission was invited to Japan to help develop aviation.
The mission was headed by Jacques-Paul Faure and composed of 63 members to establish the fundamentals of the Japanese aviation, the mission also brought several aircraft including Salmson 2A2, Nieuport, Spad XIII, two Breguet XIV, as well as Caquot dirigables.
Japanese army aviation was organized into a separate chain of command within the Ministry of War of Japan in 1919, and aircraft were being used in combat roles during the 1920 Siberian Intervention against the Bolshevik Red Army near Vladivostok.
The first aircraft factory in Japan, Nakajima Aircraft Company, was founded in 1916 and later obtained a license to produce the Nieuport 24 and Nieuport-Delage NiD 29 C.1 (as the Nakajima Ko-4) as well as the Hispano-Suiza engine.
Nakajima later license-produced the Gloster Sparrowhawk and Bristol Jupiter. Similarly, Mitsubishi Heavy Industries started producing aircraft under license from Sopwith in 1921, and Kawasaki Heavy Industries started producing the Salmson 2 A.2 bomber from France, and hired German engineers such as Dr. Richard Vogt to produce original designs such as the Type 88 bomber.
Kawasaki also produced aircraft engines under license from BMW.
In May 1925, the Imperial Japanese Army Air Corps was established under the command of Lieutenant General Kinichi Yasumitsu, it was regarded as a branch equal to the artillery, cavalry or infantry, and contained 3,700 personnel with about 500 aircraft.
By the end of the 1920s, Japan was producing its own designs to meet the needs of the Army, and by 1935 had a large inventory of indigenous aircraft designs that were technically sophisticated.
By 1941, the Japanese Army Air Force had about 1,500 combat aircraft. During the first years of the war, Japan continued technical development and deployment of increasingly advanced aircraft and enjoyed air superiority over most battlefields due to the combat experience of its crews and the handling qualities of its aircraft. However, as the war continued, Japan found that its production could not match that of the Allies.
On top of these production problems, Japan faced continuous combat and thus continued losses.
Furthermore, there were continual production disruptions brought on by moving factories from location to location, each transfer with the goal of avoiding the Allied strategic bombing.
Between these factors and others, such as the restricted strategic materials, the Japanese found themselves materialistically outmatched. In terms of manpower, Japan was even worse off.
Experienced crews were killed and replacements had not been planned.
The Japanese had lost skilled trainers, and they did not have the fuel or the time to use the trainers they did have. Because of this, towards the end of its existence the JAAF resorted to kamikaze attacks against overwhelmingly superior Allied forces.