The world's leading airline industry group has criticized governments for using scientific theory _ not fact _ in their decisions to close large swaths of European airspace because of the Icelandic volcano's ash cloud.

The International Air Transport Association has expressed its "dissatisfaction with how governments have managed it, with no risk assessment, no consultation, no coordination, and no leadership."

"It's embarrassing, and a European mess," IATA CEO Giovanni Bisignani told The Associated Press. "It took five days to organize a conference call with the ministers of transport and we are losing 200 million (dollars) per day (and) 750,000 passengers are stranded all over. Does it make sense?"

European civil aviation authorities were holding a conference call Monday about what steps could be taken toward opening airspace. Transport ministers of Britain, Germany, France and Spain were to hold another later in the day.

The International Air Transport Association, in a statement, urged governments to place "greater urgency and focus on how and when we can safely reopen Europe's skies" _ such as through more in-depth study of the ash cloud.

"We have to not just use _ as the Europeans were doing _ a theoretical model, let's try to use figures and facts," Bisignani said." It means sending test planes at certain kinds of altitudes to check what was the situation with the ashes."

While the association says "safety is our top priority," Bisignani said in the statement that its member airlines have run test flights with no problems and "they report missed opportunities to fly safely."

Bisignani said that Europe _ unlike the United States, for example _ is "not well-equipped" when it comes to planes that can test the air quality in the skies.

He estimated that once flights in Europe do resume, it would take three to six days for traffic to return to normal.