New spurts of ash from Iceland's volcano triggered fresh travel mayhem Tuesday, puncturing stranded travellers' hopes of getting home quickly despite the reopening of some of Europe's major air hubs.

While some countries including France, Germany and Belgium allowed a gradual resumption of flights, others scrapped plans to end their lockdown as authorities in Iceland said the volcanic activity was still "considerable".

Millions of people have been stranded across the globe since Europe began shutting down airspace six days ago, while the world association of airlines, IATA, says the crisis is costing the industry 200 million dollars a day.

Airlines such as British Airways and Germany's Lufthansa have been at the forefront of pressure for an immediate reopening of the airspace and had hoped that Tuesday would mark the beginning of the end of the crisis.

Eurocontrol, the body coordinating air traffic control across the continent, said around 14,000 flights scheduled in Europe for Tuesday should take place, representing around half of the normal volume.

"On a normal Tuesday, we would expect between 27,000 and 28,000. By the end of today, we expect that more than 95,000 flights in total will have been cancelled since Thursday 15 April," it said.

However British Airways cancelled all its short-haul flights after the National Air Traffic Services, which manages the country's airspace, said the situation was "worsening in some areas".

In Iceland itself, police said blasts could be seen from three separate craters, although the plume of ash from the Eyjafjoell volcano was diminishing.

"There is still considerable volcanic activity at the site and three seemingly separate craters are still erupting," a statement said.

"The plume is still rising but it is smaller and lighter, indicating that there is not much ash in it."

Eye-stinging, sulphuric dust enveloped farmland under the volcano while visibility fell to 50 metres (yards) and cars drove with headlights on during daylight.

But Sigrun Hreinsdottir, a geophysicist at the University of Iceland, said the intensity was subsiding.

"I would worry if we saw expansion of the volcano, but we are seeing the volcano shrink," she told AFP.

The French-based European Volcanic Ash Advisory Centre said the fresh ash would pass over Britain and Nordic countries but spare other parts of Europe.

While several smaller airports in Britain did resume operations, London Heathrow - Europe's biggest - remained closed.

BA said it was "still hoping" to operate long-haul flights as planned from 1500 GMT Tuesday, "however this remains subject to the full and permanent opening of airspace".
Australia's Qantas Airways extended its ban on flights to and from Europe for another 24 hours, citing "additional volcanic activity".

Aviation authorities in Ireland had also hoped to reopen its airspace at dawn but announced the ban was being extended.

Denmark's aviation authority Naviair said all its airports would remain closed until at least Wednesday and that it had pushed back a low-cost airline's test flight due to a high concentration of ash.

German authorities extended the closure of its airspace by six hours to 1800 GMT although Lufthansa was given clearance to fly visually rather than relying on instruments, and staying in constant contact with traffic controllers.

Lufthansa said it planned to carry more than 15,000 passengers on some 200 flights, around 11 percent of its normal daily schedule.

Airspace over northern Italy slowly re-opened with the first flights leaving Rome and Milan. Flights also began landing at Belgian airports, including Brussels.

And in France, Transport Minister Dominique Bussereau said 30 percent of scheduled national and international flights would fly from Paris airports.

"I am happy, I'm going to see my wife again," said an Ivorian man after stepping off a flight from Abidjan at Charles de Gaulle Airport.

A British navy ship, the HMS Albion, arrived in the northern Spanish port of Santander to pick up troops returning from Afghanistan as well as around 200 stranded holidaymakers.
Others made it home after gruelling journeys overland.

"We were supposed to fly back on Sunday," said exhausted German housewife Adelheid Jung, one of about 700 stranded tourists brought back from Spain in special buses to Frankfurt overnight.

"We were lucky to get this bus, and then our son-in-law has come to pick us up in his car to take us home to Cologne," she said, steeling herself for the 200-kilometre final stretch.

Even the world's top footballers were caught up in the chaos with Barcelona travelling by bus to Milan for a Champions League semi-final.