FRANKFURT (AFP, REUTERS) - German national carrier Lufthansa will cut its winter flight plan by "around 10 per cent" as the spread of the Omicron Covid-19 variant fuels uncertainty about travel, chief executive Carsten Spohr said on Thursday (Dec 23).

"From the middle of January to February, we see a sharp drop off in bookings", leading the airline group to cancel "33,000 flights or about 10 per cent" of its flights this winter, Mr Spohr said in an interview with the Frankfurter Allgemeine Sonntagszeitung (FAS).

"Above all we are missing passengers in our home markets of Germany, Switzerland, Austria and Belgium, because these countries have been hit hardest by the pandemic wave," he said.

Europe's largest airline group - which includes Eurowings, Austrian, Swiss and Brussels Airlines - is currently running "about 60 per cent" of flights compared with the pre-pandemic year 2019, carrying "roughly half" the number of passengers, the CEO said.

The number of cancellations would have been higher, were the group not running 18,000 "extra, unnecessary flights just to secure our landing and takeoff rights", Mr Spohr added.

The global airline industry has been battered since the beginning of the coronavirus pandemic, with countless flights grounded in 2020 as countries closed their borders.

US carriers United Airlines and Delta Air Lines on Thursday said they had  cancelled dozens of Christmas Eve flights, as the spreading  Omicron variant takes a toll on its flight crews and other workers.

Chicago-based United cancelled 120 flights for Friday, while Atlanta-based Delta said it has cancelled about 90. Both said they were working to contact passengers so they would not be stranded at airports.

The European airports association ACI Europe estimated on Thursday that the number of passengers travelling through its members had dropped 20 per cent since Nov 24, when the Omicron variant was first reported to the World Health Organisation.

Germany has placed stricter limits on travellers coming from Britain and South Africa, among others, where the new variant has caused a surge in cases.

The sudden headwind for the industry also caused Irish low-cost carrier Ryanair to cut its planned January schedule by 33 per cent this week.

Across the Atlantic, American Airlines said it was running more than 5,000 flights daily on average over the Christmas and New Year period - around 86 per cent of its flight schedule over the same period in 2019.

Domestic demand "is very strong", the company said.

Internationally, pandemic-related travel curbs or test requirements have "a dampening effect" on demand, it added, "and we have seen that in some places".

Sick pilots

On Thursday, a Lufthansa spokesman told AFP the airline had already cancelled several transatlantic flights around Christmas, after the number of pilots calling in sick became greater than normal for this time of year.

Asked whether the absences were linked to the Omicron variant, the spokesman said he "could not speculate", as he did not have any information about the causes of illness.

In total, the airline has been forced to axe six flights between Thursday and Sunday, including services to Chicago, Boston and Washington.

The lack of personnel came despite Lufthansa's "big planned reserves" of crew, the spokesman said.

Swedish national carrier SAS on Wednesday also cancelled nine flights due to the coronavirus, after scrapping some 30 flights worldwide the day before.

Lufthansa posted its first operating profit since the beginning of the pandemic in the third quarter of this year, after a difficult 18 months.

The carrier booked an underlying, or operating loss of €5.5 billion (S$8.4 billion) in 2020 and turned to the state for support.

In November, Lufthansa announced it had finished paying back the €9 billion bailout it received from the government earlier than planned.