Berlin: German airline Lufthansa cancelled about 800 flights yesterday, affecting some 10,000 passengers worldwide, after more than 4,000 pilots began a four-day walkout over job security.

Europe's biggest airline by sales said many long-haul flights to the US, including New York and Denver, were cancelled because of the strike organised by the cockpit pilots' union. However, it said it was still running many domestic flights and short-haul routes across Europe.

Other flights to the US, including Newark, New Jersey, Dallas and Chicago were scheduled yesterday, as were flights to destinations in Africa, South America and Asia.

"Usually we have 1,800 flights a day," Deutsche Lufthansa said early yesterday. "For today, we foresee about 1,000 flights planned, but there may be more flights that could be cancelled during the day," the airline warned. It offers some 160 long-haul flights to destinations worldwide.

The airline, Germany's largest, estimated the strike could cost it some $25 million (Dh91.7 million) per day.

Subsidiaries affected

Pilots for Lufthansa Cargo and the low-budget subsidiary, Germanwings, are also taking part in the strike.

Lufthansa said it was trying to rebook travellers on partner airlines or trains. Travellers unable to be rescheduled were being reimbursed for their tickets, it said.

"They're giving us the service and support to get us where we need to go," said Shane Parkinson, who was flying from Germany to Sicily, whose original flight from Frankfurt was scrapped. "They wouldn't upgrade us to business class but it could have been worse."

Germanwings said it was operating several flights over the four-day period to destinations including Britain, Greece, Spain, Bulgaria, Italy and Croatia, among others, but warned of cancellations, too.

Lufthansa, based in Cologne, owns or holds significant stakes in airlines including Swiss International Airlines, Austrian Airlines, JetBlue of the US and Britain's BMI. Those are not affected.

The pilots are seeking increased work security and want German labour conditions to apply to Lufthansa pilots hired abroad, in an effort to prevent their jobs from migrating to neighbouring countries with cheaper conditions. Lufthansa denied it was planning to relocate the jobs.

"Not one job has been moved. No Lufthansa pilot's job has been scrapped and no job cuts are planned at the moment," said Christoph Franz, the airline's deputy chairman.

The airline reached out to travellers online, too, posting a strike schedule on its website and offering updates on whether flights were cancelled or not on its Twitter feed.