United Airlines Holdings Inc.’s CEO, Scott Kirby, has expressed deep concerns about Boeing Co.’s recent safety issues, including a mid-air emergency on an Alaska Airlines flight. Kirby has reportedly vented his frustrations with Boeing’s management to colleagues and has sought support to revamp the company’s leadership. He has also engaged with US Transportation Secretary Pete Buttigieg over the grounding of Boeing’s 737 Max aircraft.

While the White House is monitoring the discussions, it is unclear what steps the Biden administration may take in response to the complaints about Boeing. Secretary Buttigieg has been in contact with the planemaker, aligning with his hands-on approach in dealing with US airline executives.

Kirby’s outspoken criticisms and the grounding of dozens of 737 Max 9 aircraft following the recent accident highlight the mounting pressure on Boeing CEO Dave Calhoun and the company’s directors. The Federal Aviation Administration has intensified its scrutiny of Boeing, requesting airlines to inspect door plugs on an older 737 model, in addition to grounding most of the Max 9 fleet and investigating Boeing’s production.

While the Transportation Department lacks legal authority to dictate changes to Boeing’s leadership, it can take enforcement actions or other high-profile steps against the company. Transportation Secretary Buttigieg emphasized the severity of concerns conveyed to Boeing leadership and underscored the FAA’s commitment to conducting a thorough review, independent of pledges made by the company.

The White House and the Transportation Department did not immediately respond to requests for comment, and both United and Boeing also refrained from immediate comment on the matter.