Hundreds of flights were cancelled on Thursday, with more expected to be scrapped on Friday, as French air-traffic controllers go on strike.
Air France, easyJet and Ryanair are some of the airlines caught up in the disruption, affecting operations from key European hubs, notably Charles de Gaulle in Paris.
Low-cost Irish carrier Ryanair was forced to cancel more than 400 flights over the two-day strike on Thursday and Friday, affecting about 70,000 passengers. Lobby group Airlines for Europe said as many as 300,000 travellers have or will face disruptions as a result of the strikes, with more than 1,500 flights already affected.
Air France said it has put plans in place to maintain its long-haul flight schedule.

Flights from UAE carriers are currently on schedule. Etihad Airways, which has a direct route between Abu Dhabi and Paris, is operating as normal today, as is the Emirates flight from Dubai to the French capital.
Some regional airlines have been affected, however. Egyptiair cancelled flights MS801 and MS802 operating between Cairo and Paris on Friday.
“Due to an air-traffic controllers’ strike at Charles de Gaulle airport, which began on Thursday and is expected to continue for two days, the French Civil Aviation Authority has requested all airlines to cancel flights to and from the airport," the airline said.
Airline bosses have criticised the strike. “Once again European families are held to ransom by French air-traffic controllers going on strike," Ryanair chief executive Michael O'Leary said.
The airline controllers' union, UNSA-ICNA, blamed France's civil aviation agency, DGAC, for its failures to modernise.
"The systems are on their last legs," the union said.
The European strikes come just weeks after the closing of airspace across the Middle East in light of the Israel-Iran-US conflict. This led to major disruption as airlines had to cancel, reroute and even divert flights mid-air.
While flights have stabilised in most of the Middle East, some airlines have still suspended service to cities such as Beirut, Amman, Tehran and Tel Aviv.