Air France said on Wednesday it expected to cancel up to 40 percent of its long-haul flights and up to 30 percent of shorter flights as a pilot strike ran into its third day.
Air France has had to notify thousands of passengers of axed flights this week via email or text message.
On Tuesday, roughly one in two long and medium-haul flights were cut, but many passengers were re-routed on alternative flights, the airline said.
The SNPL pilots union says around half its members are participating in the action over plans by the conservative government to make strikers in the airline industry give two days' notice before any walkout. Currently, they are not required to give any notice.
The industrial action, which adds to travel disarray caused by freezing temperatures across Europe, was set to run until Thursday night.
French daily La Tribune, citing unnamed sources, said Air France loses roughly 15 million euros per day during a strike, before the cost of compensating passengers.
Transport Minister Thierry Mariani said earlier this week the government was determined to push through the legislation, which would let airlines plan minimum services during a strike rather than finding out on the day that staff have not showed up.
The legislation, adopted in the lower house of parliament in January, is to be taken up by the Senate in mid-February.