Thousands of passengers will be hit by strikes in France, Italy and Portugal over the next four weeks, warn airlines.
The latest round of strikes to hit European flights starts today (Thursday) with a 35-hour walk-out by French air traffic controllers.
More than 200 flights have already been cancelled and the industrial action is expected to lead to knock-on delays and flight detours.
Over the next four weeks, eight more strikes have been announced in Italy and Portugal with more than 1,000 flights at risk of being cancelled.
"European travellers face a summer of chaos, disruption and ruined holidays due to ATC strikes," said said Thomas Reynaert, managing director of A4E, a European airline lobbying group launched in January.
"Just this week nine strike days have been confirmed for June and July and they surely won’t be the last. There has never been a greater urgency for the European Commission and the governments to act and to protect the rights of millions of European travellers affected by this unceasing strike actions.
"There is nothing stopping further ATC strikes – we need urgent action to stop these controllers from infringing on people’s rights and destroying their holiday plans."
Airline CEOs are due to meet with key industry players in Brussels on Tuesday to discuss ways to minimise the impact of strikes.
Ryanair said it has been forced to cancel 56 flights today due to the French strikes, the 11th in the past 12 weeks.
The airline’s marketing chief Kenny Jacobs said: "These strikes by French ATC workers are becoming a weekly event by now, causing chaos for families wanting to take their summer breaks but also designed to upset the plans of football fans coming from far and wide to France to enjoy the Euros
"It is simply unacceptable that this situation is allowed to persist, and we regret that once again we have been forced to cancel a number of flights due to the selfish actions of these workers."
He urged passengers to sign its petition, www.KeepEuropesSkiesOpen.com, which Ryanair will present to the European Commission once it has a million signatures. It has 200,000 signatures to date.
