The missiles “are predominantly re-entering into Japanese airspace,” Flight Service Bureau, a Florida-based aviation consulting firm, said in August. “This creates a new risk to civil aviation.”
Cathay Pacific said its plane was “far from the event location” on Wednesday, but it did not say how far. The sighting was reported to air traffic controllers in Japan, and the flight’s “operation remained normal and was not affected,” the airline said.
Korean Air said it was unclear how far the apparent missile re-entry was from its own planes, whose flights originated in Los Angeles and San Francisco.
Military weapons have sometimes downed civilian flights, including Malaysia Airlines Flight 17, which investigators say was hit by a Russian surface-to-air missile over Ukraine in 2014. While the intercontinental ballistic missiles, or ICBMs, that North Korea has recently tested are not meant for use against aircraft, they could still pose a risk to planes.
“It is something to be concerned about,” said Peter Harbison, executive chairman of CAPA — Center for Aviation, a consultancy in Sydney, Australia. But he said that while such missiles posed a danger to commercial flights, the risk was “low in terms of probability.”
Both Cathay Pacific and Korean Air said they were not taking any new precautions in response to the apparent sightings. “We have been in contact with relevant authorities and industry bodies as well as with other carriers,” Cathay Pacific said in its statement. “At the moment, no one is changing any routes or operating parameters.”
“The risk is small,” said Roger Mulberge, an aviation safety consultant based in Bangkok. “Even with the amount of air traffic you get these days, in the airspace there’s a fair amount of room.”
But North Korea’s tendency to launch without warning is “worrying,” he added.
North Korea stopped giving advance notice of its missile tests in 2014. After the North launched dozens of rockets and ballistic missiles that year, South Korea complained to the United Nations Security Council and international aviation and maritime organizations about the lack of warning.
As North Korea began testing ICBMs this year, the Federal Aviation Administration and the authorities in several other countries issued warnings about the threat of unannounced launches.
United States carriers have long been banned from flying over most of North Korea because of the risk of planes being targeted by the North’s military.
In 1998, the F.A.A. decided to allow American airlines to operate in the far east of North Korean airspace, over the Sea of Japan. Last month, the F.A.A. restricted American carriers from that slice of North Korean airspace as well, citing the “hazardous situation created by North Korean military capabilities and activities, including unannounced North Korean missile launches and air defense weapons systems.”
Flight Service Bureau recommended in early August that operators consider rerouting “over the Japanese landmass or east of it.” But even that flight path would not have been completely out of range of recent North Korean tests. On Aug. 29 and Sept. 15, the North fired missiles that flew over Japan and landed farther to the east.