Airlines were forced to cancel scores of flights to and from Italy on Saturday due to an air traffic control strike.
Ryanair cancelled 108 flights and condemned the action by Italian ATC workers.
EasyJet cancelled an unspecified number of flights due to the strike, which took place from 1pm to 5pm.
British Airways re-timed some flights but it had been forced to cancel others.
"We will be using larger aircraft, where possible, to help affected customers and are doing all we can to reduce the levels of disruption," it said.
In a statement on its website, Ryanair said: "We sincerely apologise to all customers disrupted by these unjustified strikes – the fifth such ATC strike in the last three weeks – by ATC unions who are holding European consumers to ransom.
"We call on the Italian Government and EU Commission to take action to prevent any further ATC disruptions."
The strike follows a 24-hour walkout by French air traffic controllers last week.
Ryanair repeated its call for passengers to sign its online petition, ‘Keep Europe’s Skies Open’, which it will present to the EU Commission and the EU Parliament to try to get them to take action to prevent future strikes.
