European airports are in for another busy summer as passenger numbers globally recover to pre-pandemic levels.
Airlines have said they are ready to avoid a repeat of last year's travel chaos, after strikes and staff shortages forced them to cancel thousands of flights to avoid long queues at major airports.
But air traffic control strikes, which have caused airlines to demand protections for overflights, and walkouts by airline and airport staff have continued to disrupt flights into the key tourism season.
Here is a summary of recent developments:
The Unite union on June 12 postponed the first summer strike at London's Heathrow airport including over 2,000 security workers after a better pay offer.
Meanwhile, around 100 security officers and terminal technicians at Birmingham Airport, along with aircraft refuellers employed by Menzies, are balloting for strike action. Strikes could begin in July and would severely impact the airport's operations, according to Unite.
Air traffic controller (ATC) strikes in France have led to delays and limited flights across the country, causing more air space congestion in Europe.
Most recently, French aviation regulator asked carriers to cancel a third of their flights from the Paris-Orly airport on June 6 due to a planned ATC strike. It also asked them to reduce flights by 20% at Lyon, Marseille, Nice, Toulouse, Bordeaux and Nantes, and urged passengers to postpone trips if possible.
On 6 June, Ryanair said it had to cancel 400 flights due to the 36-hour strike, most of them overflights not going to France.
Several unions representing workers in the aviation sector called a nationwide 24-hour strike for June 20 over pay and working conditions.
ENAC Aviation Authority said the strike would affect airport handling services, airline and airport staff, and air transport and associated companies. Flight delays and cancellations were also expected. The staff of Vueling also walked out, affecting the low-cost airline's flights.
Pilots at Iberia Regional Air Nostrum, who had been striking every Monday and Friday since 27 February, went on a daily indefinite strike from June 6 amid a pay dispute. The nationwide action was ongoing as of 20 June, and the airline says on its website that changes in flight schedule may apply.
Air Europa pilots in Spain also started a two-week strike on 19 June amid a wage dispute.
Spain has said it expects to receive more tourists in the summer of 2023 than before the COVID-19 pandemic.
Airport controllers at Bromma Stockholm Airport and Gothenburg's Landvetter Airport will walk out on 3 July if a new labour agreement is not reached, the Swedish Transport Workers' Union said. Workers at Stockholm's Arlanda, the country's biggest airport, will follow on 5 July, including work in X-rays, goods checks and gate reception among others.