Yokosuka Oihama Naval Airfield

Post-war demilitarization and industrial conversion. After Japan's surrender, the airfield was decommissioned as part of the dissolution of the Imperial Japanese military. The land was later acquired by Nissan Motor Co. to support Japan's rapid post-war economic growth and industrial expansion, leading to the construction of a major automobile factory.

The former airfield site is now entirely occupied by the Nissan Oppama Plant, a major automobile manufacturing facility that opened in 1961. The plant includes production lines, a dedicated shipping port (Oppama Wharf), and an extensive vehicle test track, parts of which may follow the layout of the former runways. A monument commemorating the site as the 'Birthplace of Japanese Naval Aviation' is located on the factory grounds, preserving its historical legacy.

Yokosuka Oihama Airfield, more commonly known as Oppama Airfield (追浜飛行場), holds a pivotal place in Japanese aviation history. Established in 1912, it was Japan's first naval air base and is considered the 'Birthplace of Japanese Naval Aviation' (日本海軍航空発祥の地). It was home to the prestigious Yokosuka Naval Air Group (Yokosuka Kōkūtai), which was central to the research, testing, and development of nearly all aircraft used by the Imperial Japanese Navy (IJN). Many famous IJN aircraft, from early biplanes to advanced WWII fighters like the Mitsubishi A6M Zero, were tested and evaluated here. The airfield served as the primary test flight center for the nearby Yokosuka Naval Air Technical Arsenal. After WWII, it was briefly occupied by U.S. forces before being returned to Japan.

There are zero plans or prospects for reopening the airfield. The site is a critical piece of industrial infrastructure for Nissan and is located in a densely populated urban and industrial area. The land has been completely and irreversibly redeveloped, making any return to aviation use infeasible.