Spain closed 19 northern airports including Barcelona on Saturday because of the cloud of ash blowing south from a volcano in Iceland.
Airports in Switzerland have not suffered to any great extent but three flights were cancelled and the situation could change, the authorities said. Meterologists said the cloud was drifting towards Switzerland.
An airport spokesman in Geneva said two flights scheduled for Portugal had to be cancelled, while Zurich airport said one flight to northern Spain would not be served. On Sunday, Portuguese authorities said flights in and out of Porto would be stopped until at least noon local time.
Swiss International Air Lines said in a statement that its flight operations were being conducted as scheduled except services to and from Barcelona.
Some minor delays might occur in isolated cases, especially on services to and from Spain, Portugal and North America, it added.
The Madrid government said over 400 flights would be cancelled, leaving almost 40,000 people stuck in airports stretching from the northwest to the northeast of the country.
Sweeping closures of European airspace last month disrupted the travel of millions of passengers in Europe and elsewhere, and cost airlines over €1billion SFr1.41billion in revenues.
Scientific assessments led to a decision to restrict closures to areas of higher ash concentration, after lower concentrations were found not to be damaging aircraft engines.
The European air traffic agency Eurocontrol warned on Saturday of a rise in emissions from the volcano, Eyjafjallajokull.
swissinfo.ch and agencies
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