Shares in the Scandinavian airline plunge as it canceled three quarters of its daily air traffic.

• Flights hit worldwide - except in Iceland
• Iceland volcano blast could last 'long time'

Ash from a volcano that erupted in Iceland caused Norway, Sweden and Denmark to close their airspace Thursday. Britain closed its airspace to all flights and there was major disruption in Belgium, France, Finland, Germany and the Netherlands.

Scandinavian airline SAS cancelled 635 flights, or almost three quarters of its daily air traffic on Thursday because of ash from a volcano eruption.

"So far, we have cancelled 635 flights out of 870 daily. The ones flying were mostly in Denmark and Sweden, while there was barely any traffic in Norway," SAS spokeswoman Elisabeth Manzi said.

It's still too early to say for how long traffic will be restricted, and what the financial impact will be on SAS. But it will be severe.

“The loss of revenue will amount to at least double-digit millions of kronor every day”, Sture Stölen, the IR director at SAS, told the TT newswire.

The airline usually has a turnover of some 100 million kronor ($14 million) a day.

Shares in SAS were down as much as 7 percent in Stockholm Thursday.

Budget airline Ryanair has also cancelled all flights to and from Sweden.

Last month the airline said it expects to post a pretax loss of 1 billion kronor for the first quarter due to weak demand and negative currency effects.

The governments of Denmark, Sweden and Norway collectively owns 50 percent of the Scandinavian group, which posted a loss of 2.95 billion kronor in 2009 after a loss of 6.36 billion kronor the previous year.

In February the airline announced a 5 billion kronor rights issue in a move to strengthen its troubled balance sheet. SAS had already issued new rights worth 6.0 billion kronor in the first half of 2009.