Air chaos spreads across Europe

Millions of stranded travellers face further air chaos as the volcanic ash from Iceland that has closed most of Europe's airspace continues to spread.
About 20 countries closed their airspace and some have extended flight bans into Monday. Experts say the cloud may not shift until later in the week.
Disruption is now said to be greater than that after 9/11 and the eruption shows no sign of abating.
Some airlines are making test flights to try to identify safe flight paths.
TEST FLIGHTS
Dutch airline KLM said it flew a Boeing 737-800 up to the usual maximum altitude of 13km (8 miles) on Saturday and Germany's Lufthansa said it flew 10 planes to Frankfurt from Munich at altitudes of up to 8km.
Lufthansa and Air Berlin said the decision to close much of Europe's airspace was not based on proper testing and that their aircraft showed no signs of damage after flying without passengers.
"The decision to close the airspace was made exclusively as a result of data from a computer simulation at the Volcanic Ash Advisory Centre in London," Air Berlin chief executive Joachim Hunold told the Bild am Sonntag newspaper.
"Not one single weather balloon has been sent up to measure how much volcanic ash is in the air."
Lufthansa spokesman Klaus Walter told Bild: "The flight ban, made on the basis just of computer calculations, is resulting in billion-high losses for the economy.
"In future we demand that reliable measurements are presented before a flying ban is imposed."
KLM chief executive Peter Hartman, who was on board the plane, said there was "nothing unusual" about the flight.
"If the technical examination confirms this... we then hope to get permission as soon as possible to partially restart our operations," he added.
The tests were conducted at the request of the European Union to see whether travel disruption could be alleviated.
More trials are due to take place later on Sunday in countries including Britain, France and Italy.
UK Transport Secretary Lord Adonis, said "urgent discussions" were taking place between European and international agencies to ease the chaos.
"We want to be able to resume flights as soon as possible, but safety remains my paramount concern," he said.
Weather experts say wind patterns mean the cloud is not likely to move far until later in the week.
The impact is likely to exceed the airspace shutdown after the 11 September 2001 attacks, the International Civil Aviation Organisation said.