The CEO of United Airlines is frustrated about ongoing manufacturing problems at Boeing, and his airline will consider alternatives to buying a future, larger version of the Boeing 737 Max.

The United Airlines CEO says he is “disappointed” in ongoing manufacturing problems at Boeing that have led to the grounding of dozens of United jetliners, and the airline will consider alternatives to buying a future, larger version of the Boeing 737 Max.

United Airlines CEO Scott Kirby said Tuesday that Boeing needs “real action” to restore its previous reputation for quality.

Kirby’s comments came one day after United disclosed that it expects to lose money in the first three months of this year because of the grounding of its Boeing 737 Max 9 jets.

United has 79 of those planes, which federal regulators grounded more than two weeks ago after a panel blew out of an Alaska Airlines Max 9 in midflight, leaving a gaping hole in the plane. Investigators are probing whether bolts that help hold the panel in place were missing or broke off.