Air France-KLM issued a 2018 profits warning today on the back of ongoing strikes by unions in France.

The giant European carrier described the full year operating result as “expected to be notably below 2017”.

The airline revealed that the industrial action will cost at least €300 million this year.

Additionally, Air France-KLM faces a €350 million hike in its annual fuel bill and €100 million in adverse currency “headwinds” due to the strengthening of the euro.

The group issued first quarter figures as staff staged a 13th walkout at Air France this year.

Air France-KLM’s first quarter loss widened to €118 million including a €75 million impact of strike action, compared to a loss of €33 million for the same period last year.

Overall unit costs in the quarter rose 2.1%, of which 1.7% was related to the strikes.

Passenger numbers rose by 5.2% to 22 million in the three months and the group reported that long-haul booking load factors for the next four months are ahead of this time last year.

“The global context remains uncertain given the current geopolitical environment, labour wage inflation pressure, strengthening of the euro compared to other currencies and rising fuel price trends,” the airline said.

“Due to the strike impacts on the 2018 Air France results, the management will carefully continue to manage the financial structure of the group and its growth plan.”