Tens of thousands of passengers across Europe have been affected as French air traffic controllers began a two-day strike at the start of a busy summer holiday season to protest against understaffing and “toxic management”.

The strike by two French unions led to the cancellation of hundreds of flights and multiple delays. It was expected to affect nearly 300,000 people, according to industry association Airlines for Europe.

“This strike is intolerable,” said the head of Airlines for Europe, Ourania Georgoutsakou.

“French air traffic control already delivers some of Europe’s worst delay figures, and now the actions of a minority of French air traffic control workers will needlessly disrupt the holiday plans of thousands of people in France and across Europe.”

Half of flights in Nice, France’s third-largest airport, and a quarter of flights at Paris Orly and Paris Charles de Gaulle, one of Europe’s busiest hubs, have been cancelled.

Disruption is expected to worsen later today, the eve of the French school holidays.

“We’re trying to stay positive, there are worse things, but it’s annoying,” Nadia Rivet, a 51-year-old bank employee, told AFP.

She was planning to spend six days in Paris, but her flight from the southwestern city of Pau was cancelled.

“Everyone has the right to strike, but it’s punitive. Air traffic controllers aren’t the worst off,” she said.

The strike forced the cancellation of 933 flights on Thursday, said the DGAC civil aviation authority, which asked airlines to cancel some of their flights to ensure there were enough controllers on duty.

The strike involved 272 air traffic controllers from a workforce of about 1000 staff on duty, the DGAC said.

Transport Minister Philippe Tabarot said carriers would lose “millions of euros” as a result of the strike.

“Constantly choosing dates that will cause the most inconvenience to passengers does not seem to be the right approach,” he said.

Ryanair, Europe’s largest airline, said it cancelled 170 flights, affecting 30,000 passengers.

“Once again, European families are held to ransom by French air traffic controllers going on strike,” chief executive Michael O’Leary said.

Most affected Ryanair passengers were not flying to or from France but were flying over French airspace.

Airports in southern France have been hit particularly hard, with 30% of flights cancelled in cities including Lyon and Marseille. Photo / AFP

“It makes no sense and is abundantly unfair on EU passengers and families going on holidays,” O’Leary said.

He urged European Commission chief Ursula von der Leyen to take “urgent action” to protect overflights, among other reforms.

British budget airline easyJet said, “We are extremely disappointed”, noting that the performance of French air traffic control was the leading cause of airspace delays in Europe this summer.

UNSA-ICNA, the second biggest labour group in the sector, launched the strike to demand better working conditions and more staff.

The union is protesting against “chronic understaffing”, the planned introduction of a clock-in system, outdated equipment and “toxic management practices that are incompatible with the requirements of calm and safety”.

It was joined by the third-largest union, USAC-CGT.

The main union, SNCTA, said it had no plans to join them.

Airports in southern France were hit particularly hard, with 30% of flights cancelled in cities including Lyon and Marseille.

Air France said it had been “forced to adapt its flight schedule”, but its long-haul network was not affected.

The situation is expected to become increasingly tense over the next 24 hours at Paris airports and Beauvais, about 75km north of Paris, where the DGAC has ordered a 40% reduction in the number of flights.

Business aviation, particularly in Nice and Le Bourget near Paris, has also been significantly affected.

Eric Nouen, a 60-year-old travelling to Montpellier from French Guiana, in South America, said he was not going to complain.

“Right now, everyone could go on strike. Everyone has a reason right now.”

- Agence France-Presse