Iceland volcano ash closes airspace in northern Germany
Ash from an Icelandic volcano has forced the closure of major airports across northern Germany.
Officials have grounded all flights in and out of Hamburg and Berlin. Bremen airport was also closed for several hours before reopening.
Traffic is returning to normal in other parts of northern Europe, a day after about 500 flights were cancelled.
The Grimsvotn volcano, which erupted on Saturday, seems to have stopped spewing ash, an Icelandic official said.
The German authorities closed Bremen and Hamburg airports in the early hours of Wednesday. Traffic at Berlin's airports was halted at about 1100 (0900 GMT).
Later, the country's air traffic control agency said the ash level was "no longer critical" at Bremen and allowed it to reopen.
Nobody is happy about the grounding of aircraft in northern Germany in smaller airports as well as the bigger ones in Berlin, Hamburg and Bremen.
But nor was there the outburst of discontent which came with the cancelled flights in Britain the previous day.
One stranded passenger at Bremen said: "One has to take it as it is. That is the way it is. Safety is first. When an ash cloud moves towards us and the planes are endangered by this, I would not like to be on board a plane."
There is some unease within the industry about what they see as different regulations in different countries. No airline chief executive has matched Ryanair's Michael O'Leary in his vociferous condemnation.
About 700 flights out of 8,000 on a normal day were expected to be cancelled in Germany, Europe's air traffic control body Eurocontrol said in a post on its Twitter page.
The cloud could also affect parts of Poland but there are no flight restrictions elsewhere in Europe, Eurocontrol said.
Experts say particles in the ash could cause jet engines to stall.
German Transport Minister Peter Ramsauer told public television ARD: "Security is the top priority but we can say that the situation will get better later today."
The country's transport authorities have taken a tough view on the potential dangers posed by the ash, says the BBC's Stephen Evans in Berlin.
There has been no outright criticism of the decision from German airlines, but there is unease in the industry that Germany's rules regarding flying through volcanic ash are different from the rest of Europe, our correspondent says.
The head of the country's airport organisation said Europe-wide rules were needed.Larger particles
France's civil aviation authority has said it expects very little disruption to air traffic and was not expecting to close any of the country's airspace.
Air traffic in Norway, Denmark and the UK was disrupted on Tuesday, with Scotland, Northern Ireland and northern England especially badly hit.
The UK closures were condemned by Ryanair chief Michael O'Leary on Tuesday. He accused authorities of "bureaucratic incompetence" and said the airline had safely sent two planes into ash zones over Scotland.
Britain's weather service said the concentration of volcanic ash in UK airspace would decrease significantly over the course of Wednesday.
The volcano began erupting last Saturday, sending clouds of ash high into the air. But it appears to have stopped emitting ash at 0200 GMT on Wednesday, said Hrafn Gudmundsson of the Icelandic Meteorological Office.
Experts say the eruption is on a different scale to that of the Eyjafjallajokull volcano last year, when millions of travellers were stranded amid concerns about the damage volcanic ash could cause to aircraft engines.
European Union transport commissioner Siim Kallas said: "We do not at this stage anticipate widespread airspace closure and prolonged disruption like we saw last year."
Icelandic President Olafur Grimsson told the BBC: "The eruption is gradually being diminished and the ash cloud is definitely smaller than it has been so we are pretty optimistic now."
The ash particles from Grimsvotn are larger than those from Eyjafjallajokull, and so fall to the ground more quickly.