Hundreds of flights to and from Canada remained grounded Friday on both sides of the Atlantic Ocean as volcanic ash clogged airspace across northern Europe, threatening to scuttle even Prime Minister Stephen Harper's plans to travel to Poland.
There was barely a trickle of traffic between Canada and Europe as an erupting volcano in Iceland continued belching ash into the sky, forcing the closure of airspace over Britain, France and the Nordic countries.
Dozens of European airports remained closed for a second straight day. Air Canada and Air Transat were both forced to cancel all of Thursday's flights to London, Paris and Frankfurt.
On Friday, Air Canada added Munich, Zurich and Geneva to its list of destinations that were off-limits.
One Air Transat flight was cleared to depart Scotland for Toronto, while the CBC reported that a Thomas Cook flight from Vancouver had also been allowed to depart for Scotland, but was diverted to Manchester.
Authorities in Britain, where flights have been cancelled until today, also said Friday that some transatlantic evening flights would be cleared to depart from airports in Glasgow, Edinburgh and Aberdeen.
Harper and political rivals Michael Ignatieff, Jack Layton and Gilles Duceppe were among those Canadians waiting to find out whether their travel plans would be thwarted.
Harper and a delegation of Canadian dignitaries, including the leaders of all three federal opposition parties, were scheduled to fly out of Ottawa early this morning to attend the funeral of Polish president Lech Kaczynski and his wife.
Kaczynski's presidential plane crashed in heavy fog last Saturday as it approached Smolensk, Russia, to mark the 70th anniversary of the Katyn Massacre.
All 96 people aboard, including Poland's senior military command, the country's central bank president and more than a dozen political leaders, died in the crash.
All airports in Poland were closed Friday with no immediate word on when they would reopen.
Even if Harper's plane had a place to land, safety concerns would still be taken into account when deciding whether or not to fly, said Andrew MacDougall, a spokesman with the Prime Minister's office.
"We continue to monitor the situation closely," MacDougall said.
"We are mindful of the risks the volcanic ash presents to air travel. As always with the prime minister's travel - and keeping in mind the tragic events in Poland - proper safety procedures will be followed."
So far, Harper, U.S. President Barack Obama, Russian President Dmitry Medvedev and German Chancellor Angela Merkel remained among those planning to attend and no one had cancelled.
Kaczynski's family insisted Friday they wanted the funeral to go forward as planned, but there was no denying the ash cloud was moving south and east.
The air traffic agency Eurocontrol said almost two-thirds of Europe's flights had been cancelled.
"The skies are totally empty over northern Europe," said Brian Flynn, deputy head of Eurocontrol. "There will be some significant disruption of European air traffic tomorrow."
The agency said about 16,000 of Europe's usual 28,000 daily flights were cancelled Friday - twice as many as were cancelled a day earlier.
Only about 120 trans-Atlantic flights reached European airports compared to 300 on a normal day, and about 60 flights between Asia and Europe were cancelled.
The International Air Transport Association said the volcano was costing the industry at least $200 million a day.