The Defense Agency said four Japanese F-15 jets headed to the area Thursday morning, but no further action was taken.
The islands known as Senkaku in Japanese and Diaoyu in Chinese have been at the center of a territorial dispute. The purchase of the islands by the Japanese government earlier this year from private Japanese owners set off massive anti-Japanese rallies in China.
Japanese ships have been patrolling the area on the lookout for approaching Chinese ships.
Chinese ships have darted in and out the waters in that area in recent months. Violations by Chinese planes of air space are more unusual.