By Cristina Gallardo

Thousands of airline passengers were grounded Thursday as French air-traffic controllers began a two-day walkout over working conditions that triggered flight cancellations at the start of the summer vacation period.

Ahead of the strike, France's civil aviation agency, DGAC, asked multiple carriers to reduce flights landing at or taking off from several airports in the country, including Paris Charles de Gaulle, Orly and Nice, it said on its website.

Flights crossing the country's airspace, even those not destined for France, faced delays and rerouting, affecting routes to Belgium, Spain, Portugal, Greece, and Morocco.

Ryanair on Thursday said it canceled 170 flights, including those passing over the country, affecting more than 30,000 passengers.

Easyjet said it canceled 124 flights scheduled for Thursday and a further 150 flights that were due to take off Friday. The airline estimated between 20,000 and 25,000 passengers a day would be affected.

A spokeswoman for easyJet said the performance of French air-traffic controllers was the "leading cause of airspace delays in Europe this summer" and called for long-term solutions.

Iberia Group, which includes Iberia, Air Nostrum and Iberia Express, said it canceled 23 flights scheduled for Thursday. Deutsche Lufthansa Group, Vueling and Wizz Air were also among the carriers announcing flight cancellations for the same day.

According to Flightradar, Paris Charles de Gaulle has so far had 118 cancellations and 84 delayed flights, while Nice Cote d'Azur Airport has had 93 cancellations and 21 delayed flights.

UNSA-ICNA, France's second-largest air traffic controllers' union, said its strike, which extends into Friday, is in protest of understaffing and outdated equipment.

DGAC wasn't available for further comment.

French Transport Minister Philippe Tabarot said he was "determined to stand firm" and described the decision to strike during the busy holiday season as "unacceptable."

In a post on social-media platform X, Tabarot warned that the impact on France's national carrier Air France was likely to run into "millions of euros." He added that this was "a burden that will ultimately fall on the French taxpayer."

Air France declined to comment.

Write to Cristina Gallardo at cristina.gallardo@wsj.com

(END) Dow Jones Newswires

July 03, 2025 06:17 ET (10:17 GMT)

Copyright (c) 2025 Dow Jones & Company, Inc.