Air travel has been badly disrupted by a series of disputes across Europe.
French air traffic controllers have gone on strike in protest against a pan-European deal to modernise the sector. The restructuring row has forced airlines to scale back departures from Paris.
Half of the short- and medium-haul flights at Orly airport and a quarter of similar flights at Charles de Gaulle airport have been cancelled.
Disruption is likely to carry on until Saturday.
The action follows a strike by Lufthansa pilots. Even though that walk-out has been suspended for two weeks while talks take place it will take a few days before flight operations can get back to normal the airline says.
Now British Airways cabin crew have backed a call for a strike over pay and conditions next month.
It is their second attempt to take industrial action after a court forced their union Unite to abandon plans for a 12-day stoppage over Christmas.
No dates have been set for the latest walk-out but union leaders are reassuring passengers the strike will not be held during the Easter holiday at the start of April.