United Airlines Holdings Inc has ordered 25 new Boeing 737 MAX aircraft for delivery in 2023, the U.S. airline said on Monday.

The airline also moved up the delivery of 40 previously ordered MAX aircraft to 2022 and 5 to 2023.

"With a number of our aircraft nearing the end of their lifecycle and the growth opportunities that we know will exist in the COVID-19 recovery period, this agreement will help us to grow as demand returns," Chief Commercial Officer Andrew Nocella said in a memo.

The accelerated global rollout of COVID-19 vaccines has fueled hopes of an economic rebound and an uptick in travel demand.

The 737 MAX was grounded in March 2019 after two deadly crashes. Regulators in the United States, Europe and Britain are among those who have approved the jet's return to flight.

The New York Times had earlier reported the news of the order.

(Reporting by Sanjana Shivdas in Bengaluru and Tracy Rucinski; Editing by Arun Koyyur and Sriraj Kalluvila) ((SanjanaSitara.Shivdas@thomsonreuters.com; within U.S. +1 646 223 8780, outside U.S. +91 80 6749 1642; Twitter: @SanjanaShivdas;))