Air France Airbus A380 F-HPJC docked at terminal E at Paris CDG airport. The French carrier has 10 of the type in service, delivered between October 2009 and June 2014. Each aircraft is fitted with 516 seats in four classes (F9, 80C, 38W, 389Y).

MIAMI – The flight crew and ground staff unions of Air France announced on Sunday a new two-day strike that will take place on April 10th and 11th, the fourth and latest move in the payment dispute some workers have with the French flag carrier since February.

The last work stoppages made by Air France’s staff were on February 22nd, March 23rd, and 30th. The new dates are in addition to the previous plans the unions had to strike on Tuesday and Saturday; in the same week, workers from rail operator Société Nationale Des Chemins de Fer Français (SNCF) also begin a series of strike days.

In a statement made in Sunday, the three pilot unions slammed the “obstinate refusal” of the airline’s management “to take into consideration the least of their demands.” The pilots have been joined by unions representing flight attendants and ground personnel, which later issued a joint statement saying Air France “does not take seriously the determination of the employees and the unions.”

Air France personnel are demanding a six percent salary increase, with unions arguing the airline should share the wealth with its staff after strong results in 2017. But management insists it cannot offer higher salaries without “jeopardizing growth in an intensely competitive sector.”

READ MORE: Air France Strike Will Affect 25% of Its Flights

The French carrier told AFP late Sunday it “deplored the new strike which comes even as management is urging unions to come to new meetings on the negotiations.” The airline said it was necessary to maintain a dialogue “to limit the impact on the still-fragile economic situation of the company.”

However, Air France is trying to control the situation with passengers by updating flight schedules 24 hours in advance. It recommends its customers that may be affected to check periodically on its website whether their flights are operating or not before going to the airport. The airline is also offering passengers the chance to postpone their trip or change their ticket at no extra cost.

READ MORE: Air France Pilots Will Strike Again on March 23

Air France is set to bring in a 0.6% pay rise from April 1st and another 0.4% increase from October 1st, along with bonuses and promotions equivalent to a 1.4% raise for ground staff; yet, it is seen by unions as inadequate.

The French state owns 17.6% of the carrier as part of the Air France-KLM group, Europe’s second-biggest airline and one which has been plagued by strikes and labor disputes in its French operations in recent years.