At the latest launch on November 29, flight crews on planes run by airlines such as Korean Air and Cathay Pacific reported sightings of missile activity while in the air.
While North Korea has claimed that their new weapon has put all parts of the United States within reach of a devastating strike, US officials say the latest test was a failure since the missile broke apart on re-entry as the airliner witnessed.
The representative of the Ministry of defense Colonel Robert manning reported that the missile flew about 1,000 km before falling into the sea of Japan, reports Reuters.
"At the moment, no one is changing any routes or operating parameters", the Hong Kong-based airline said in a statement. Cathay Pacific's crew reported seeing the weapon re-enter the Earth's atmosphere, while Korean Air said its pilots "saw a flash".
Any missile launches must be reported to the International Civil Aviation Organization to assure the safety of civilian aircraft.
But US intelligence sources reportedly said they knew three days in advance and watched the missile preparation.
In the case of the latest launch of the Hwasong-15, which experts say can strike anywhere in the United States with a nuclear payload, North Korea used a mobile stand possibly to avoid detection, according to Panda. The sightings are believed to have been of North Korea's latest intercontinental ballistic missile (ICBM) test. "We remain alert and (will) review the situation as it evolves".
Meanwhile, Senator Lindsey Graham said Sunday on "Face the Nation" that preemptive war in North Korea is "becoming more likely" as the country's improving missile technology presents an increasing threat. The French airline expanded its no-fly zone over North Korea as a result.