In 1972 I was at the command center in Seoul for a year.
The North would nearly daily get a bucket load of jets to fly at the border at nearly supersonic speed. At the last moment they would turn off so as to not cross the border.
Each time we would scramble our jets out of Kimpo airbase to go up to meet the threat.
Seoul is about thirty miles south of the border and at the speed these jets go they could be on top of the capital it mere moments.
It was always nervous time when this occured.