A cabin blowout and the grounding of more than 170 Boeing jets have rekindled frustration among airlines over the planemaker’s struggle to contain a series of safety and supply crises.

Alaska Airlines and United Airlines, together have 70% of the MAX 9 fleet and have canceled hundreds of flights.

And with provisional checks turning up loose bolts in some of the grounded planes, the return to service could be delayed, with implications for the earnings of both airlines.

Some analysts have already trimmed first-quarter profit estimates for both the carriers.

National Transportation Safety Board (NTSB) Investigator-in-Charge John Lovell examines the fuselage plug area of Alaska Airlines Flight 1282 Boeing 737-9 MAX, which was forced to make an emergency landing with a gap in the fuselage, in Portland, Oregon, U.S. January 7, 2024. NTSB/Handout via REUTERS

However, the scale of impact depends on how long the planes remain grounded.

Boeing CEO Dave Calhoun acknowledged mistakes and told staff he and many customers had been “shaken to the bone.” Boeing must work to earn their confidence, he said.

“In the next couple of weeks, we will be under siege,” Calhoun warned, according to people familiar with his remarks.