The transport ministry instructed nine low-cost carriers to improve safety standards and avoid prioritising cost-cutting.

The missing data deepens the puzzle of what caused the deadly air disaster in Muan, South Korea, late last month.

South Korea will extend runway safety areas and redesign infrastructure after the crash of a Jeju Air Co. flight last month that killed almost everyone on board, sparking criticism that the design of the airport might have exacerbated the accident.