Agency. More than 30,000 passengers’ travel plans have been affected by a two-day strike by France’s air traffic control. Thursday and Friday’s strike severely affected flights within France as well as other European countries.

Budget airline Ryanair said it had to cancel more than 170 flights. More than 30,000 passengers’ leave plans have been disrupted due to this, the company said. Two French trade unions have called for a strike to demand improvements in working conditions.

25 percent of flights at Paris’ main airports and 50 percent at Nice airport have been canceled. France’s Transport Minister Philippe Tabarot has strongly criticized the strike as unacceptable. “It is irresponsible to go on strike at such a time when people are going on leave,” he said.

Ryan Air Chief Executive Michael O’Leary has accused air traffic controllers of holding European families hostage. “The strike in France’s airspace has affected not only flights to France, but also flights going to the UK, countries like Ireland, Spain and Greece, which is unjust and unwise,” he said. He called on European Commission President Ursula von der Leyen to intervene and to ensure minimum service during the strike.

France’s civil aviation authority has urged airlines to reduce flight schedules at various airports across the country. Flights at Paris’s Charles de Gaulle, Orly and Bove airports are expected to be affected by up to 40 percent on Friday.

The airline for Europe, Europe’s leading airline, said the strike could not be tolerated and warned it would be a major problem for passengers during the holiday season. EasyJet, another company that provides cheap air services, also expressed deep disappointment over the strike and called for a solution.

Ryanair said it had to cancel more than 800 flights last month alone due to the recent conflict in the Middle East. However, the company claimed to have operated more than 109,000 flights in June and that cancelled flights were less than 1 per cent.