United Airlines cast doubt Tuesday on future orders and deliveries of Boeing 737s after it was forced to ground dozens of planes following the dramatic Alaska Airlines incident earlier this month.

The U.S. airline grounded its fleet of 79 Boeing 737 Max 9 aircraft on January 6, a day after a panel blew off the Alaska Airlines plane mid-flight, leaving a hole in the fuselage and forcing an emergency landing.

Although there were no fatalities or serious injuries in the January 5 incident, U.S. regulators grounded 171 jets from the 737 Max 9 fleet with the same configuration as the plane involved in that drama.

United announced Monday that it predicts the aircraft will remain out of action through the end of January, leading to losses in the first quarter of 2024.

In a conference call Tuesday, United’s chief financial officer Michael Leskinen said 31 out of the 107 aircraft United expects to take delivery of this year are Boeing 737 Max 9 aircraft.

“It is unrealistic at this time to believe all of those aircraft will deliver as currently planned,” he said.

Alongside its Max 9 orders, United also has 277 as-yet-uncertified Boeing 737 Max 10 aircraft on order through the rest of the 2020s, and options to purchase 200 further aircraft, Leskinen told the conference call.

“We also expect a reduction in orders and deliveries from Boeing in 2025,” he said, noting that orders of 737 Max 10s would also likely be affected.

The Max grounding was “kind of straw that broke the camel’s back with believing that the Max 10 will deliver on the schedule we had hoped for,” he said.

“So we are working through an alternate plan,” he added.

United’s shares were up almost seven percent in mid-day trading, following the release of strong fourth-quarter results after the market closed Monday, while Boeing’s shares slipped by around 0.7 percent.