Britain and Ireland reimposed flight bans early Saturday as the huge cloud of volcanic ash from Iceland kept millions of air travellers stranded across Europe.
After Friday saw some 16,000 flights cancelled by the drifting dust amid the biggest airspace shutdown since World War II, air traffic had controllers warned that the cloud was likely to cause fresh travel disruption.
That was confirmed early Saturday when Britain's air authorities reintroduced a flight ban on the country's entire airspace.
"Current forecasts show that the situation is worsening throughout Saturday," said NATS, which manages British airspace. It also extended the existing by six hours to 7:00 pm (1800 GMT).
Ireland also reimposed a total flight ban in its airspace until at least 1700 GMT.
"No commercial passenger flights including North American traffic will operate from any Irish airport during this period," said a statement from the Irish Aviation Authority.
Earlier, Italy's civil aviation authority announced airspace across the north of the country would be shut down for eight hours on Saturday as the ash cloud passed.
Eurocontrol, which coordinates air traffic control in 38 nations, had said the ash was moving east and southeast and warned of "significant disruption of air traffic (Saturday)".
Justifying the widespread airport closures aviation officials have explained that airplane engines could become clogged up and stop working if they tried to fly through the ash.
In the past 20 years, there have been 80 recorded encounters between aircraft and volcanic clouds, causing the near-loss of two Boeing 747s with almost 500 people on board and damage to 20 other planes, experts said.
The International Air Transport Association meanwhile warned Friday of the economic fallout from the eruption of the Eyjafjallajokull volcano in southeast Iceland.
According to their figures it was costing airlines more than 200 million dollars (230 million euros) a day.
More smoke and ash had spewed out of the volcano Friday, building up the cloud, which then blew east to stretch from the Atlantic to the Russian capital Moscow and from the Arctic Circle south to Bulgaria.
Europe's three biggest airports - London Heathrow, Paris-Charles de Gaulle and Frankfurt - were closed by the ash, leaving passengers stranded across the world as a global flight backlog built up.
Eurocontrol said only 12,000 of the daily 28,000 flights in the affected zone would take off Friday, after about 6,000 were cancelled the day before.
Austria, Belgium, Britain, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Hungary, Latvia, the Netherlands, Poland, Romania, Slovakia, Spain, Sweden and Switzerland shut down all or most of their airspace.
Lithuania and Norway had gradually reopened theirs.
Budget airline Ryanair cancelled all its flights in northern Europe and the Baltics until 1200 GMT Monday.
Germany closed all its airports Friday, forcing flag carrier Lufthansa, Europe's biggest airline, to cancel all its flights.
The Eurostar Channel tunnel rail service reported thousands of passengers rushing to get places on its London-Paris trains. It laid on three extra trains, but still could not keep up with demand.
The shutdown also played havoc with diplomatic schedules.
Poland had considered delaying Sunday's funeral of president Lech Kaczynski because the cloud threatened the flights of US President Barack Obama and other world leaders, but a senior presidential aide insisted it would go ahead.
German Chancellor Angela Merkel was stranded in Lisbon, Portuguese President Anibal Cavaco Silva in Prague and a UN Security Council delegation cancelled a trip to the Democratic Republic of Congo that would have flown out of Paris.
Even US pop superstar Whitney Houston had to take a car ferry from Britain to Ireland for a concert in Dublin.
And comedy legend John Cleese, in what sounds like a sketch from his Monty Python days, reportedly paid 5,100 dollars for taxi ride from Oslo to Brussels.
The volcano on the Eyjafjallajokull glacier erupted on Wednesday, sending ash drifting towards Europe at an altitude of about eight to 10 kilometres (five to six miles).