Three Asian airlines are making changes to flight paths to avoid a North Korean rocket launch due to take place between 12 and 16 April.
Philippine Airlines, Japan Airlines and All Nippon Airways have announced changes to several routes.
North Korea has moved into its rocket into place on the launch pad and allowed journalists to view it.
Pyongyang says the rocket will put a satellite into orbit to mark the 100th birthday of late leader Kim Il-sung.
But opponents of the move fear it is a disguised test of long-range missile technology.