On April 15, 1964, , , and merged to form Japan Domestic Airlines. On May 15, 1971, the airline merged with Toa Airways to form Toa Domestic Airlines; on April 1, 1988 the merged airline renamed itself to Japan Air System. Japan Air System merged into Japan Airlines in the early 2000s.
Nearly all of the aircraft used in the Japan Domestic Airlines fleet were consisted of NAMC YS-11s. Both airlines had a similar color scheme from the beginning, usually blue and white, or with a blue tail. In the early 1980s the proprietary color schemes were replaced by a rainbow-stripe scheme but featured different routes and domestic services within Japan. Japan Domestic Airlines focused mostly on mainland to island flights, while Toa Japanese Airlines focused on more domestic mainland flight plans and services.