Transcript for North Korea's dangerous missile landing

We turn next here to north Korea's dangerous new launch, and what we did not know at the time. The commercial airliner filled with passengers flying in the same region, that intercontin intercontinental ballistic missile flying longer and higher than ever before, landing just minutes before an airliner with 300 people on board passed that area. Here's ABC's Martha Raddatz tonight. Reporter: While this could some day hit most of the U.S., it was sending shock waves around the world. The more immediate danger we are just learning tonight was right in the area from where the missile was recklessly launched, in busy commercial air space. As the missile was descending, flight data shows an air france-777 with 323 people on board traveling from Tokyo to Paris, less than ten minutes after the plane passed northwest of this island, landing in the water near the spot the air France plane had just flown. The crew of the plane had no idea they were in danger. It was coming in from out er space. Reporter: They say they constantly analyze dangerous flyover Zones and they say the flight was operated without incident, but the Pentagon has said North Korea's missile launches into busy air space and heavily traveled seas are done with no coordination. Martha is with us, and they have their own missile test planned in California. But unlike the north Koreans, the defense department will put out an announcement to warn those in the region? Reporter: That's right, David. We always put out those advisories and never launch near flight paths or sea lanes, David. Martha Raddatz in Washington.

This transcript has been automatically generated and may not be 100% accurate.