A strike by Air France pilots protesting plans to transfer jobs to the airline's low-cost subsidiary Transavia has been extended into its second week.
The industrial action began a week ago and was originally scheduled to last seven days (see news, September 15).
But it will now last until at least Friday, and possibly indefinitely, union bosses have warned.
France's transport minister Alain Vidalies said the move could place the airline "at stake".
He said on French radio: "There must be a positive approach in this situation, otherwise I think that it's the fate of the company that could be at stake.
"The low-cost sector is not a choice, it's an obligatory move, that's reality. I think pilots are fully aware of this."
The ongoing strike is protesting plans to move jobs to Transavia to keep up with competition, which unions claim will affect working and pay conditions.
Air France said that it expects to operate around 41 per cent of its flights today; 65 per cent of its pilots have walked out.
It has previously said it will consider negotiating benefits based on seniority of pilots who agree to work for its low-cost airline.
However, it said it will not agree to demands that the contracts of Transavia pilots carry the same terms as those flying under Air France.
The carrier's CEO Frederic Gagey last week said that the strike action could end up costing the airline €10 million to €15 million a day.
He today said: "Air France has maintained constant dialogue with its pilots in order to reach an agreement to benefit the group's growth and competitiveness.
"I deplore that our concrete proposals to reassure our pilots have not been met with a reasonable response as yet. On behalf of the whole company, I would like once again to apologise to all of our clients and their families. We are doing all we can to help them."
Air France is offering its passengers travelling between September 15 and 26 the chance to either "modify their ticket to reschedule their flight between September 27 and October 8 inclusive, free of charge, subject to available seats when choosing their rescheduled flight or receive a voucher valid for one year on Air France or KLM flights for a rescheduling flight for after October 8, a change of destination or departure point, or to cancel their tickets".
Earlier this month, the airline announced it wanted to invest €1 billion in growing Transavia, which would help create 250 new pilot jobs and grow its fleet to 100 aircraft.
It said by 2017, Transavia "will rank among the leading low-cost carriers in Europe", and there are plans to move the business to a more "pan-European scale".