Various unions representing air traffic staff around Europe have stated that possible industrial action could occur this summer. If these unions decide to strike, flights in Europe will experience delays and cancellations. Eurocontrol, the agency that manages European flights and air traffic controls in Europe, is hoping to reach an agreement with the unions as negotiations continue. Flights in Europe are experiencing additional issues this summer, with airspace in Europe being constrained by the Russia-Ukraine conflict. Air traffic control centers are also dealing with worker shortages as many air traffic controllers retired during the pandemic.
See "Potential strikes by European air traffic unions could cause delays and cancellations this summer", Tom Espiner, Katy Austin, BBC, July 7, 2023