There are lots... All served by KE and OZ.
mainly from Seoul Kimpo, Pusan Kimhae, Daegu, Pohang, Ulsan, Wonju .etc etc
lots of domestic flights between those cities are served... probably countless....
Most used fleet for Korean Domestic is 737, A300, A330, MD80, F-100, and even sometimes 747.
The biggest mistake made by most human beings: Listening to only half, understanding just a quarter and telling double.