(Reuters) -Boeing is in the early stages of developing a new single-aisle airplane that would eventually replace the 737 MAX, the Wall Street Journal reported on Monday, citing people familiar with the matter.

Earlier this year, CEO Kelly Ortberg met with officials from Rolls-Royce Holdings in the UK to discuss a new engine for the aircraft, according to the report.

The U.S. planemaker has also been designing the flight deck of a new narrow-body aircraft, the report said, adding that development remains in the early planning phase, with final decisions yet to be made.

The planemaker told WSJ that its recovery plan remains on track, with priorities including the delivery of roughly 6,000 back-logged commercial airplanes and the certification of previously announced models.

Reuters could not immediately confirm the report. Boeing and Rolls-Royce did not immediately respond to a Reuters' request for comment.

The 737 MAX entered service in 2017 but was grounded globally in 2019 after two fatal crashes killed 346 people.

Both incidents slashed Boeing's profits and triggered lawsuits, investigations, and a criminal probe by the U.S. Department of Justice. The Federal Aviation Administration lifted the grounding order in 2020 during the COVID-19 pandemic.

Last Friday, the FAA said it would allow the planemaker to issue airworthiness certificates for some 737 MAX jets, starting this week. This authority had been revoked in 2019 following the second fatal crash involving the model in Ethiopia.

The move comes as Boeing continues to face regulatory scrutiny.

In early 2024, the FAA imposed a production cap of 38 737 MAX planes per month after a mid-air cabin panel blowout on a new Alaska Airlines jet, which was later found to be missing four bolts.

The Alaska Airlines incident prompted the U.S. Justice Department, under then-President Joe Biden, to open a criminal investigation and declare that Boeing was not in compliance with a 2021 deferred prosecution agreement made after the company had misled the FAA during the 737 MAX regulatory certification process.

(Reporting by Nilutpal Timsina in Bengaluru; Editing by Sherry Jacob-Phillips)