The boss of budget airline Ryanair has warned that flight delays and cancellations will continue "right throughout the summer" as airports suffer amid staff shortages.
Michael O'Leary, chief executive of Ryanair, said passengers should brace for a "less than satisfactory experience", with flight delays due to last across the peak season and some airlines cancelling between 5% and 10% of flights.
He told Sky News this was "deeply regrettable".
The CEO said: "This problem is going to continue particularly at airports like Gatwick and Heathrow right throughout the summer.
"It will be worse at weekends and better during the week."
According to Mr O'Leary 99% of Ryanair flights are getting away and that the experience was so far better at its Stansted base than other UK airports, but admitted it will be a "struggle through the summer".
He went on to blame the problems on shortages of airport staff across air traffic control, baggage handling and security.
Ryanair was not immune to the issues, he added, with last weekend seeing 25% of its flights delayed by air traffic control issues and a further 15% by airports handling delays.
Mr O'Leary said Brexit was compounding the disruption caused as demand ramps up after pandemic restrictions were lifted, with airports unable to hire workers from abroad to fill posts.
He said: "There are hundreds of thousands of jobs in the UK that frankly British workers don't want to do.
"These problems will not be resolved until we start allowing people in to do the jobs."
The comments come after Heathrow asked airlines on Monday to cut 10% of flights at two terminals, while easyJet started cancelling thousands of summer flights.
The move by Heathrow affected around 5,000 passengers at Terminals 2 and 3 on approximately 30 flights.
Images emerged on Friday of a huge pile-up of passengers' luggage to add to passenger woes with delays and cancelled flights.
Here is a list of industrial action planned by Ryanair staff:
Belgium
Trade unions claimed they were forced into action because Ryanair was not respecting Belgian labour law covering such issues as the minimum wage or pay of cabin staff.
Unions representing Ryanair workers in various European countries said on Friday that they were planning a strike in Belgium from June 24 to June 26.
Portugal
Portugal-based cabin crew have said a three-day strike will go ahead on June 24, 25 and 26, which could impact dozens of flights between the UK and the popular holiday destination. Workers are demanding compliance with Portuguese law and better working conditions, Portugal's union of civil aviation personnel SNPVAC said in a statement.
"This mobilisation is not only an opportunity to put the spotlight on multiple attacks on workers' dignity and to make this reality known but also a moment to show unity and solidarity against dumping", the union added.
Spain
The strike in Portugal comes just one day after Ryanair's Spanish cabin crew announced a six-day strike. The action will take place on June 24, 35, 26 and 30, and on July 1 and 2.
Workers have blamed discontent with working conditions and pay as the reason for the series of walkouts.
Italy
Unions representing staff in Italy called for a 24-hour strike on June 25 to coincide with walkouts in both Spain and Portugal.
Unions FILT-CGIL and UIL Trasporti said they sought improved pay and conditions after staging a four-hour stoppage earlier in June.
France
Union members employed by the no-frills airline in France have threatened a walkout on June 25-26 adding to the disruption for travellers across Europe.
Flights from Toulouse, Marseille and Paris Beauvais airports to Morocco, Italy, Spain, Portugal, Greece, Corsica, England, Scotland and Ireland are likely to be affected.
