New York (CNN) American Airlines announced Sunday it will extend cancellations of flights on the Boeing 737 Max through December 3.

While the announcement leaves open the possibility that American will resume flights on the plane for the busy holiday season, it also underlines the duration of the 737 Max grounding, which is now in its sixth month. Boeing originally hoped to get approval for the aircraft to fly again months ago

American Airlines AAL American had previously canceled 115 daily flights on the aircraft through November 2 . This latest move will result in approximately 140 canceled American flights per day, the airline said. Announcing the cancellations so far in advance givestime to assign new aircraft to 737 Max routes or rebook customers whose flights were canceled. American said customers on canceled flights can be rebooked or receive a refund.

United Airlines UAL Southwest LUV took a similar step Friday, canceling 90 daily flights due to the 737 Max until December 19., which has more 737 Max planes in its fleet than any other US airline, has canceled about 180 daily flights through January 5.

The 737 Max was grounded worldwide in March following two fatal crashes in less than six months. The grounding halted delivery of new planes and has forced the cancellation of thousands of flights around the world.

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