The travel plans of tens of thousands of airline passengers at the start of the working week have been wrecked as industrial action intensifies across Europe.

British Airways has cancelled 40 flights on Monday because of the first French air-traffic control strike of the year, plus a further six departures because of a week-long stoppage by some cabin crew. Most of the cancellations are between London and French cities, but six flights on the Heathrow-Barcelona link have been grounded, along with services to Milan and the three big Swiss cities, Zurich, Basel and Geneva.

The strike by staff at control centres in Brest and Bordeaux runs until Friday 10 March, with controllers at the south of France centre in Aix-en-Provence stopping work between Tuesday and Thursday.

The air-traffic controllers are taking action over a range of issues, including rostering and pay. They say their counterparts in Germany earn much more for less work.

The French Civil Aviation Authority, the DGAC, has asked airlines to reduce their flight schedule in west and south-west France, affecting many services between the UK and the Iberian Peninsula.

BA says it will be using larger aircraft, where possible, to help cope with cancellations. It is allowing any passenger booked to fly to or from any French airport, as well as Madrid and Barcelona, to reschedule their flight for the following week without penalty.

The airline also warns: “There may also be some disruption on roads and public transport to/from airports on some days so customers should allow extra time for their journeys.

Air France has grounded many more services, mainly domestic flights to and from Paris Orly. Cancellations include 20 flights to and from Toulouse, 12 serving Brest and 10 to and from Bordeaux.

Passengers heading further afield, including to Bilbao, Lisbon and Casablanca may also be affected. In addition, Air France is facing a strike by its own staff on Tuesday.

Ryanair, which flies more passengers in Europe than any other airline, has cancelled 44 flights. But the airline’s marketing director, Kenny Jacobs, said: “We call on the French Government and European Commission to take immediate action to prevent thousands of European consumers from having their travel plans disrupted by a tiny group of ATC unions going on strike.

"They cannot stand idly by and allow another summer of disruption and travel misery for European consumers to take place."

The UK’s biggest budget airline, easyJet, says it expects to cancel between 30 and 40 flights on Monday, which will be mainly on French domestic services.

The stoppage will cost airlines millions of pounds in lost revenue and extra costs.