DUBLIN (Reuters) - Ryanair thinks February or the start of March is the most realistic timetable for it to start flying the grounded Boeing 737 MAX aircraft, CEO Michael O’Leary said on Thursday.

FILE PHOTO: Ryanair CEO Michael O'Leary holds a news conference in Machelen near Brussels, Belgium October 9, 2018. REUTERS/Francois Lenoir

The Federal Aviation Administration (FAA) needs to approve proposed software and training changes by Boeing BA.N for the best-selling plane that has been grounded since March in the aftermath of two fatal crashes in five months.

Major U.S. airlines have canceled flights of the MAX into December, while Southwest Airlines Co LUV.N has canceled flights into early January.

Ryanair, which is one of the biggest customers for the MAX with 135 firm aircraft orders and 75 options, thinks January is a best-case but unlikely scenario.

After the FAA has finished its review, the plane will need approval by the European Union Aviation Safety Agency (EASA) and the MAX200 model flown by Ryanair will require additional approvals.

“The best outlook is the first aircraft would come in January. The more realistic outcome: the end of February/March,” O’Leary told journalists after the airline’s annual general meeting.

“If it flies in North America this side of Christmas, I think we are pretty secure we will be back flying some time (around) end-February/March,” he said.

O’Leary said the current delivery timetable depends on Boeing getting approval for service in the United States toward the end of November “we believe we are about two months behind that,” he said.

O’Leary said he “would hope” to see the FAA and EASA certify the aircraft together, but that was not certain.

“I think they (the FAA and EASA) are largely on the same page but they don’t agree on everything,” O’Leary said. “It is clear that at the moment most of Boeing’s time and effort is focused on addressing the FAA first, because until the FAA certifies it, it is not an issue for EASA.”

Ryanair has already cut the number of MAX planes it will fly in the summer of 2020 to 30 from 60 and further delays could lead to further cuts, he said.

But he added that Ryanair was in a good position to retrain pilots on any systems updates as it has two MAX simulators.

If the MAX was never certified, it would be “devastating” for the industry due to order backlogs at the major aircraft manufacturers, he said.

“What’s our Plan B? We don’t have a Plan B,” O’Leary said.