Ryanair’s boss told the BBC that quality was improving but the incident had shown there was “more to be done”.
It comes after an unused door fell off a Boeing 737 Max 9 operated by US-based Alaska Airlines.
Ryanair does not use Boeing’s 737 Max 9 aircraft but operates the Max 8 variant and has Max 10s on order.
The airline is one of Boeing’s biggest customers for the 737 Max family, with more than 100 in service and due to have some 400 more by 2034.
Ryanair’s chief executive Michael O’Leary said that he expects delivery delays to affect its capacity.
Asked in an interview with the BBC if he had complete confidence in Boeing’s quality control processes after the incident which saw an unused door fall off, the Ryanair boss said “no”.
But he added that his airline did now have “more confidence” in plane maker Boeing.
Mr O’Leary also said that a delivery of 12 planes towards the end of last year had been “in terms of defects the best deliveries we’ve had in three years”.
He acknowledged what happened with the Alaska Airlines flight had been serious but said the industry always learned from incidents.
Ryanair will deploy more engineers to oversee quality control at US factories in Seattle and Wichita building aircraft and fuselages for the airline.
Mr O’Leary said that Boeing made good planes, but compared the relationship to a marriage: “I can be in love with you and still occasionally criticise some of your personal habits. I think that’s the same with Boeing.”
He suggested that the management team at Boeing “needs to be improved” following the incident, although he gave his support for Boeing’s current chief executive David Calhoun, stating that he is “doing a stellar job in very tough circumstances”.
Mr O’Leary added: “We don’t need more senior management changes in Boeing.”
On Monday, Boeing announced that an outside party would also be brought in to assess its production practices.
It will also check the work of the firm that supplies and installs the parts involved in the accident.
Last week, the US regulator extended the grounding of 737 Max’s with similar fuselage panels, while United and Alaska Airlines have said they were extending the cancellations of any flights involving the 737 Max 9 through until Wednesday.
The Federal Aviation Administration (FAA) also said it would conduct an audit of the plane’s production line, adding it believed there were “significant problems” with the 737 Max 9 jet as well as “other manufacturing problems”.
Announcing the latest measures, Stan Deal, who heads up Boeing’s commercial division, said the company was “not where we need to be”.
Scrutiny of Boeing has been renewed after the blowout on the Alaska Airlines flight from Portland, Oregon to California, which forced an emergency landing but resulted in no serious injuries.
The US aerospace giant has been struggling to restore confidence after crashes in 2018 and 2019 involving a different plane in the 737 Max group killed 346 people.
Poor design of a piece of its flight control system was found to play a role in those crashes, and authorities grounded its popular 737 Max planes globally for more than 18 months. Poor oversight by the FAA was also cited.
On Tuesday, Boeing also announced that it had appointed Kirkland H. Donald, a former Navy admiral, as the independent advisor responsible for overseeing a review of its quality control systems for its commercial aircraft.
He and a range of experts will provide Boeing bosses, including Mr Calhoun, with a series of recommendations.
