If the ash cloud were to drift in another direction flights could be sent around or above it.
The ash cloud resulted from an eruption in the Eyjafjallajoekull area of Iceland.
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Scientists working on an ash cloud detection system believe that airlines will soon be able to do just that.
In 1982, a British Airways 747 flew through an ash cloud during the eruption of Mount Galunggung in Indonesia.
President Obama has cut short his visit to Ireland to avoid possibly being grounded by the ash cloud from Iceland.
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"Other contributing factors include the volcanic ash cloud and current economic climate affecting both airline and traveller decisions, " he said.
Yet this week's meeting in Reykjavik was different and not just because signs were emerging of another flight-grounding Icelandic ash cloud.
Fulham arrived in Hamburg by plane on Tuesday after airspace reopened following disruption caused by the volcanic ash cloud from Iceland.
Earlier on Sunday it was reported the Dutch airline KLM had flown through the ash cloud without the test plane being damaged.
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Ryanair has already paid out 27m euros to compensate people left stranded by the ash cloud, BBC transport correspondent Richard Westcott reports.
The airline is not expecting a rush of new claims, because it has settled its ash cloud debts already, our correspondent adds.
Madrid's large airport, so far unaffected by the ash cloud, could handle extra flights with passengers then continuing their journey north by land.
Using ATDnet, Dr Bennett and his colleagues were able to identify 790 bolts which had descended from the ash cloud created by Eyjafjallajokull.
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Ryanair said its 90-minute flight at 41, 000ft showed there was "no visible volcanic ash cloud or evidence of ash on the airframe, wings or engines".
The meeting came after criticism from the airline industry that governments took an over-cautious approach to the ash cloud crisis last month, grounding flights unnecessarily.
The airport said bmibaby's cuts to routes, as part of the wider economic climate, accounted for 180, 000 of that figure and May's ash cloud the rest.
Passenger numbers at Cardiff Airport dropped by 200, 000 last year, with the airport blaming a cut in capacity by a low-cost airline and the ash cloud.
The ash cloud is now so big that airlines have been cancelling flights in and out of the capital, Jakarta, 450km (280 miles) to the north-west.
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The high-speed channel rail link, Eurostar, said it has carried an extra 50, 000 passengers in the five days since air travel was disrupted by the ash cloud.
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Dame Deirdre Hutton, of the Civil Aviation Authority (CAA), said there had been detailed consultation with experts to reassess the tolerance of planes to the ash cloud.
Flight restrictions have been extended until at least 0100 BST on Monday and forecasters say the ash cloud could remain over the UK for several more days.
The Reds were forced to abandon plans to fly direct to Spain as a result of the volcanic ash cloud that has caused travel chaos across northern Europe.
Things were made worse by the fact that the computer models of the ash cloud's dispersion gave only a very broad sense of where the ash might be.
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The planned modifications to both cars were delayed due to the volcanic ash cloud that left the teams stranded in Shanghai for days after the Chinese Grand Prix last month.
If meteorologists and vulcanologists developed a dynamic model of the ash cloud's progress, it might be possible to keep more airports open, and to reroute planes to get passengers moving again.
Eurocontrol, the European air traffic management organization, sees no impact on the European mainland for now, but shifting winds may carry the ash cloud to parts of Scotland and Ireland within the next 24 hours.
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But Brian Flynn, deputy head of operations for Eurocontrol, told the BBC that while half of the European landmass could be clear of ash cloud, that did not mean half of the flights could go ahead.
Usually, the prevailing south-westerly wind would take the ash cloud away from Europe and over the polar region, but a high-pressure area is bringing it over Europe, where it is sitting and barely moving as the ash spreads.
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