France, July 3 -- As the summer holiday season gets underway, travel plans for thousands of passengers have run into some unexpected headwinds.

A strike by French air traffic controllers is causing widespread disruption across the country, with cancellations rippling through airports from the sunny Mediterranean coast to the bustling Paris region.

On Thursday, holidaymakers at Nice Airport - France's third busiest - faced a frustrating start, as half of all flights were grounded.

A similar fate met passengers in Bastia and Calvi, while airports in Lyon, Marseille, Montpellier, Ajaccio and Figari saw around 30 percent of flights cancelled.

In Paris, where Charles de Gaulle and Orly typically handle up to 350,000 passengers daily during...