Alaska Airlines cancels all Boeing 737 MAX 9 flights through Saturday

Alaska Airlines said on Wednesday it will cancel all flights on Boeing 737 MAX 9 jets through Saturday as it conducts inspections after a cabin panel blowout on Friday, which Boeing suggested was caused by a "quality" issue.

The U.S. Federal Aviation Administration (FAA) on Saturday grounded 171 Boeing jets installed with the same panel after the emergency landing, including Alaska's 65 MAX-9s, that have forced the cancelling about 20 percent of its daily flights.

United Airlines, the other U.S. 737 MAX 9 operator with 79 of the planes in its fleet, separately said it has canceled 167 MAX 9 flights on Wednesday and expects "significant" cancellations on Thursday as well.

The Chicago-based carrier said it is able to operate some planned flights by switching to other aircraft types.

United said it is still awaiting final approval for the full inspection process for the grounded jets.

Alaska Airlines said it still needs revised inspection and maintenance instructions from Boeing that must be approved by the FAA before it can begin flying the planes again.

"We will only return these aircraft to service when all findings have been fully resolved and meet all FAA and Alaska's stringent standards," Alaska Airlines said.

Transportation Secretary Pete Buttigieg declined to say on Wednesday when the FAA may allow the planes to resume flights.

"The only consideration on the timeline is safety," Buttigieg told reporters. "Until it is ready, it is not ready. Nobody can or should be rushed in that process."

Boeing CEO Dave Calhoun acknowledged errors by the U.S. planemaker on Tuesday, telling staff the company would ensure an accident like the mid-air Alaska Airlines panel blowout "can never happen again."

The company's top planemaking official, Stan Deal, also told a town hall meeting at its Renton, Washington 737 factory that Boeing acknowledges "the real seriousness of the accident" as it launches checks into its quality controls and processes.

Calhoun told CNBC separately on Wednesday a "quality escape" was at issue in the MAX 9 cabin blowout that left a gaping hole in the plane that had just been in service for eight weeks but added there are key questions.

"What broke down in our gauntlet of inspections? What broke down in the original work that allowed for that escape to happen?" Calhoun said.

He said a quality escape is "a description of what people are finding in their inspections... anything that could potentially contribute to an accident."

Calhoun said he has spoken to Buttigieg and FAA Administrator Mike Whitaker to ensure there is no repeat of any cabin panel blowout on any 737 MAX 9 after Friday's incident.

Alaska Airlines and United Airlines said on Monday they had found loose parts on multiple grounded aircraft, raising new concerns among industry experts about how Boeing's best-selling jet family is manufactured.

The U.S. National Transportation Safety Board is also focused on whether the recovered cabin panel that blew off had been properly attached or if the bolts were actually present.