Air France managed to reduce its workforce only through voluntary departures in its previous restructuring programme, but is now seeking to
agree another €1.8 billion ($2 billion) in cost savings as it comes under continued pressure from low-cost and Gulf carriers.
Management signalled “a 10 percent drop in long-haul routes” if no deal is reached soon, said three labour leaders who met with management.
The possibility of forced layoffs was also evoked, two labour leaders said.
No precise numbers were mentioned.
Unions expect that between 9 and 14 routes could be cut, with each plane employing around 350 people.
Air France's management denied in June media reports that 3,300 jobs could go.
The airline is seeking to reach agreement on the new restructuring plan by the end of September, according to labour leaders, or says it will go ahead with the plan to cut routes.
It also has to resolve a dispute with pilots under the previous restructuring programme that would see parts of their compensation cut.
The airline shed 9 percent of its workforce, or 6,413 employees, in 2012-2014 through voluntary departures and aims to entice another 800 to leave this year.
Nevertheless the airline has had trouble keeping up with competition, and an attempt last year to mount a major expansion of its low-cost unit sparked a costly strike by pilots that led management to backtrack.
Air France-KLM saw its losses deepen by 3 percent in the first half of this year to €638 million.