British Airways and Virgin Atlantic appealed for passengers booked on long-haul flights next week to consider giving up their seat to make way for travelers still stuck following flight disruptions.

A week of airspace closures caused by ash clouds gusting from Iceland's Eyjafjallajokull (pronounced ay-yah-FYAH-lah-yer-kuhl) volcano caused the worst breakdown in civil aviation in Europe since World War II. More than 100,000 flights were canceled and airlines are on track to lose more than $2 billion.

"It's a very difficult situation, and we've had to deal with a lot of complexity, aircraft stuck in different parts of the world, crew stuck in different parts of the world," said British Airways chief executive Willie Walsh.

Flight authorities in Europe say the majority of the continent is now free of volcanic ash, and most airline services are operating as normal. Several carriers said they are adding extra flights to help the stranded return home.

Iceland's civil protection agency said Eyjafjallajokull was still spewing ash, but that the plume was now around 3 kilometers high — not large enough to reach jet streams. Winds are now gusting from the south east — away from Europe, said Olof Baldursdottir, of the civil protection agency.

Most airports in Iceland — including Keflavik International Airport and Reykjavik International Airport — were closed.

"There are still a lot of tremors in the volcano, but the plume is now less than 3 kilometers high and the ash is falling mainly locally," said Baldursdottir.

Pall Einarsson, a geophysicist at the University of Iceland, said Eyjafjallajokull was being closely monitored, and spewing ash in much smaller quantities than at the beginning of its eruption.