(CBC) -- About 370 flights to and from Scotland and Northern Ireland were cancelled Tuesday as a cloud of ash from an Icelandic volcano continued to affect air travel.
Brian Flynn, head of network operations at Eurocontrol, the European air traffic agency, warned that up 500 flights could be affected, including in some Scandinavian countries.
In Norway, two daily flights between the mainland and the Arctic islands of Svalbard cancelled until further notice. Occasional flights to and from Iceland and Stavanger in western Norway have also been cancelled.
Air Greenland cancelled two daily flights between Greenland and Copenhagen after Greenland airspace partly closed. Air Iceland cancelled flights to and from three destinations in Greenland.
In Denmark, authorities said airspace was closed in the northwestern part of the country, while ash caused some delays and cancellations in Copenhagen.
As of mid-day Tuesday, Heathrow airport had not been affected, CBC reporter Nahlah Ayad said in an interview from London.
"The good news is is that so far, the European transport officials are saying that they don't expect this to last as long as last time or to be as bad as last time partly because the concentration of the ash itself will be low compared to last time and also experts are saying that the particles in this ash cloud are heavier than last time so they're falling faster and closer to Iceland than they did last time."
This latest volcanic eruption in Iceland has so far not packed the same punch as last year's. In April 2010, another volcanic eruption grounded planes across northern Europe for five days, stranding some 10 million travellers. Thousands of flights were grounded and airlines lost millions of dollars after the Eyjafjallajokull volcano blew.
This time, there seems to be a more measured response. While flights have been cancelled in Scotland, airports remain open. And airlines are being given more leeway in deciding whether its safe for their planes to fly.
Because of what happened last year, British government officials said they are now better prepared to avoid a similar mass grounding of planes. New guidelines can determine which airline fleets are safe enough to fly through low- and medium-density ash clouds, Phillip Hammond, Britain's Transport Secretary told CBC News.
"Since then, a lot of work's been done with the engine manufacturers, with the airframe manufacturers, airlines, with other regulators around the world who have experience of volcanic ash conditions."
The result is that regulators have raised the levels of ash through which they believe aircraft can fly safely.
The ash cloud caused U.S. President Barack Obama to cut short his visit to Ireland on Monday.
Meanwhile, Barcelona's soccer team was to travel to London on Tuesday, two days ahead of schedule, for Saturday's Champions League final against Manchester United. Barcelona is making the trip early to avoid having its Champions League travel plans disrupted for a second consecutive year by volcanic ash.