An Air Self-Defense Force F-15 fighter jet went missing after taking off from Komatsu Air Base in Ishikawa Prefecture on Monday afternoon, the ASDF said.
The fighter was conducting training with a crew of two aboard when radar contact with it was lost around 5:30pm over the Sea of Japan about 5 kilometers west-northwest of the base, it said.
The ASDF said it found some floating objects in the area where the plane disappeared from radar during its search and rescue operation.
A person believed to be a crew member was located in the Sea of Japan, with a rescue being mounted, NHK reported.
The Kanazawa Coast Guard Office in the prefecture said it received a call around the same time reporting a red glow off the coast of Kaga near the base.
The missing fighter belonged to a squadron that functions as enemy aircraft in tactical flight training, according to the ASDF.
Japan has occasionally seen accidents involving its air force, including in 2019 when an F-35A stealth jet crashed into the sea after the pilot suffered spatial disorientation.
The crash sparked a scramble to recover the pilot and secrets onboard the plane.