According to Channel NewsAsia, the move has come after the July 27 missile launch by North Korea into the Sea of Japan, Singapore Airlines said on Tuesday.
A spokesman said on Monday that the flight crew of CX893 had reported a suspected sighting of Pyongyang's latest missile test. The missile flew ten times higher than the global space station and then back down to Earth.
The crew of a Cathay Pacific airplane flying from San Francisco to Hong Kong reported seeing the North Korean missile "blow up and fall apart" at the end of its test flight.
Cathay Pacific told the Guardian.
North Korea's Hwasong-15 intercontinental ballistic missile reached an altitude of about 4,475 km (2,780 miles) during its 53-minute flight.
Cathay Pacific did not reply to a request for comment by publication time, but in a response sent out earlier to other media, the airline confirmed the incident and responded to the potential threat posed by North Korea's missile tests.
The sighting was reported to air traffic controllers in Japan, and the flight's "operation remained normal and was not affected", the airline said.
While Cathay Pacific's flight last week wasn't impacted, and there is generally a low chance that a North Korean missile will hit a plane, experts say Pyongyang's missile tests could still endanger future commercial flights.
South Korea said its northern neighbor regularly fails to issue notices to airmen (NOTAM) when conducting missile launches.
North Korea has developed ballistic missiles powerful enough to reach their intended targets, including those as far away as the continental US, and nuclear warheads for those weapons, but the North has struggled with re-entry vehicle technology, which ensures that the warhead survives the flight.
"Coupled with the rogue regime's need to master missile guidance and targeting, the re-entry failure underscores the challenges facing the country's weapons program, according to the official".
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".