The German aviation authority, DFS, announced that the country's airspace would remain closed until at least 2 a.m. local time on Tuesday, dashing the hopes of millions of passengers who have been stranded for days. The closure of airspace over Germany and much of Europe is costing the airline industry millions of dollars.

However, European Union officials say they are optimistic that much of the airspace above the continent will soon reopen. Only a fifth of flights took to the air on Sunday, but some say this figure could rise to a half on Monday.

Spain, which holds the bloc's rotating presidency, has organised a telephone conference of EU transport ministers to assess the situation and has ordered a full study into the economic impact created by the volcanic ash.

A senior EU official said the current situation was not sustainable. "We cannot wait until the ash flows just disappear," said Transport Commissioner Siim Kallas. Speaking at a press conference in Brussels, he added that he hoped that 50 percent of European airspace would be risk-free on Monday.

Test flights clear

Pressure to lift the no-fly zone has been strongest from European airlines, which have launched flights to gather information about the danger of the volcanic cloud damaging jet engines.

Germany's flag carrier, Lufthansa, Air France, British Airways, and Dutch carrier KLM have so far reported no problems.

"The conditions were perfect and the aircraft encountered no difficulties," a British Airways spokesman said, though the jumbo jet used was going in for tests and data analysis.

A grouping of the continent's 36 major carriers called on governments for an "immediate reassessment" of the restrictions, saying they were having a "devastating impact" on the industry. They questioned whether the measures taken were proportionate.

"Airlines must be able to fly where it is safe to fly and make decisions accordingly," the Association of European Airlines said. "It is what our passengers demand of us."

Europe at a standstill

About 30 countries have closed or restricted their airspace due to passenger safety fears, catching 6.8 million passengers in a global backlog, according to the international airports council, ACI.

"More than 6.8 million passengers have been affected so far and European airports have lost close to 136 million euros (183 million dollars)," said its European head Olivier Jankovec. A total of 313 airports had been paralysed by the restrictions, he added.

cb/Reuters/AFP
Editor: Chuck Penfold