"Vulcanologists and meteorologists now have a better understanding of the ash. ... We had to make sure that we didn’t jeopardize safety. ... But if the same thing happened again, we wouldn’t have to close the same amount of airspace. ... We now have three different concentration levels of ash. ... Firstly, where it is not safe to fly, secondly, where planes should take precautions and thirdly, where there are low concentrations and they need not take precautions."
Joe Sultana vid Eurocontrol i The New York Times om flygbranschens lärdomar av vulkanutbrottet vid Eyjafjallajökull - läs mer om utbrottet här.