Transcript for MH17 Flight Path Declared Safe for Travel
we asked the question, why was this jet allowed to fly in this airspace? How many planes are flying above dangerous hot spots every day? Reporter: When you board a plane, you know where you are going. But how are you getting there? You might be flying over something like this. That's what Malaysia flight 17 did. Flying right over the fighting in eastern Ukraine. Why? Malaysia airlines says its route, like a highway, wasn't closed down. It was just told to stay above 32,000 feet. It doesn't matter if someone says, well, you're okay above 32,000 feet, maybe you want to be a little bit more conservative. Reporter: As Russia took over crimea, that airspace was closed to commercial jetliners in April. But international aviation officials did not close the airspace over eastern Ukraine. Even as tensions escalated, and even after a warning two weeks ago from nato that separatists were training on longer range anti-aircraft missiles. It is very hard to understand why the information from a war zone where a war is getting hotter and people are now saying that there are medium and long range missiles being used, why wasn't that cut off as a flight route? Reporter: It is tonight. After the crash, the restricted area expanded to eastern Ukraine. So now jetliners will have to fly around, over the north, or a southern route. Each detour could mean about ten extra minutes and an additional fuel cost of up to $1,500, as well as paying the countries they fly over. It all adds up, which is why many airlines still choose to fly over other hotspots around the world. Even ones the U.S. Warns about. Including the middle east and Afghanistan. Changing all those international flight routes would be chaos. An example, the area mh-17 flew through. 16 other airlines used that same
This transcript has been automatically generated and may not be 100% accurate.