Iceland Set to Reopen Airports

LONDON—Iceland's top carrier said the country will reopen its main airport late Monday after aviation authorities had restricted flights over the island following a volcanic eruption that sent a plume of ash and dust high into the atmosphere.

Local carrier Icelandair Group said If the latest weather and ash forecasts are accurate and there are no further eruptions, the country's main Keflavik International Airport will reopen Monday and flights will be back on schedule Tuesday.

The broader impact on travel following the eruption of the Grimsvötn volcano, which began on Saturday, appeared to be easing, although the ash cloud from the eruption is expected to reach northern Scotland and parts of Ireland by Tuesday. Besides Iceland, the other airspace closure took place over parts of Greenland, Danish authorities said.

According to graphics on the website of the Met Office, the U.K.'s weather forecaster, ash is expected to enter Scottish airspace by midnight Monday at between eight kilometers and 12 kilometers, altitudes at which some aircraft fly. It added ash would affect other parts of the U.K. and Ireland later in the week.

The Civil Aviation Authority, the U.K. aviation regulator, said any potential disruptions would be minimal and that there wouldn't be a repeat of last year's events, when blanket airspace closures were imposed over the U.K. The CAA said it was better able to cope with ash this time, "with processes in place and lessons learned," a spokesman said.

"Our No. 1 priority is to ensure the safety of people both onboard aircraft and on the ground," said CAA Chief Executive Andrew Haines. "We can't rule out disruption, but the new arrangements that have been put in place since last year's ash cloud mean the aviation sector is better prepared and will help to reduce any disruption in the event that volcanic ash affects U.K. airspace."

Iceland's Eyjafjallajokull volcano erupted in April last year, spewing into the atmosphere clouds of ash that drifted over much of Europe, forcing air-traffic controllers to ground commercial aircraft for about a week for safety reasons. Ten of thousands of flights were cancelled and the travel plans of millions were disrupted. Under European regulations, airlines were left to pick up the tab for passengers unable to complete their journeys.

The ash cloud will have its biggest impact on those intending to fly to and from Iceland, but also international flights to and from the U.S. that follow jet streams close to Iceland as they look to keep fuel costs to a minimum.

Still, none of the major European airlines was expecting a severe impact on operations Monday.

Air France-KLM Sunday was forced to reduce the altitude of a Paris to San Francisco flight that goes over the area where cloud is, a spokesperson for the French airline said Monday, adding that those actions added five minutes to the duration of the flight.

KLM said it also changed some flight paths to the west coast of the U.S. Sunday and Monday, which would lead to delays of about 15 minutes.

Under what airline authorities deem dense conditions, where there is four grams or more of ash per 10 cubic meters of air, aircraft will be excluded from flying. However, they will be allowed to fly where ash is between two and four grams per 10 cubic meters, provided they have a safety report and the approval of their engine manufacturers that the plane can cope.

Ryanair Holdings PLC Chief Financial Officer Howard Millar said he wasn't concerned, adding that there wouldn't be as much disruption as last year as the ash this time is "heavier and falling more quickly."

He added the degree of "panic and hysteria" shown by European regulators and governments last year wouldn't be repeated.

But some airlines already have adopted methods to mitigate any potential impact. Ryanair, for example, started imposing a €2 levy per passenger to protect itself against costs it may incur for accommodating stranded passengers under European duty-of-care legislation.

At 1612 GMT, Air France-KLM's shares traded down 4.5%, Deutsche Lufthansa AG's shares fell 3.5%, while International Consolidated Airlines Group SA's shares traded down 5.1%. Europe's largest travel operator, TUI Travel PLC, was down 3.2% and its rival, Thomas Cook Group PLC was off 3.8%.

—Alessandro Torello in Brussels, David Pearson in Paris, Bart Koster in Amsterdam and Charlie Duxbury in Sweden contributed to this article.