It hadn't previously announced the changes before this week.
Airlines operating routes between Korea and the United States are changing flight paths to avoid areas that may be exposed to missile launches from North Korea.
The world-renowned carrier changed the flying route of its Seoul- Los Angeles flights since last July as a safety precaution against the North Korean missile tests, stated a report in Channel NewsAsia. North Korea joined the ICAO in 1977, but the last time it warned the organization of an impending missile launch was in February 2016.
In a leaked internal memo, the airline's general manager for operations, Mark Hoey, told the staff, "Today [date unspecified] the crew of CX893 reported, 'Be advised, we witnessed the DPRK missile blow up and fall apart near our current location.'" The Democratic People's Republic of Korea or DPRK, is the official name for North Korea.
Pilots aboard a Cathay Pacific flight reported seeing what they believed were the remnants of the event.
"There are no current routes that fly through a unsafe zone", said an Asiana Airlines official.
"We do take the matter seriously and are monitoring the situation very closely and will reroute our flight paths where necessary", a Cathay Pacific spokesperson added.
European airlines Lufthansa and Air France-KLM shifted their paths in August after two North Korean test launches in July.
Airlines are already largely avoiding airspace controlled by North Korea in the Pyongyang flight information region, one of the sources said.
Travelers who are concerned should know the chances of an airplane colliding with a missile are extremely low: One safety analyst estimates that it is less than a billion to one.
Katherine Lam is a breaking and trending news digital producer for Fox News.