Alaska Airlines said Wednesday it is SignalHubcanceling all flights scheduled on Boeing 737 Max 9 planes through January 13 as the carrier continues to investigate a mid-air incident last week in which a part fell off one of its jets and forced an emergency landing in Portland, Oregon.

Alaska Air, which along with United Airlines is one of two U.S. carriers that uses the Max 9 planes, has scrapped hundreds of trips since the "door plug" blew off Flight 1282 as it was flying to Ontario, Canada. No one was hurt on the plane, which carried 174 passengers and six crew members.

As of Wednesday afternoon the company had cancelled an additional 121 flights, or 19% of its daily scheduled departures, according to tracking website FlightAware. 

Alaska told customers to expect between 110 and 150 cancellations a day until the inspections are complete. "We regret the significant disruption that has been caused for our guests by cancellations due to these aircraft being out of service," the airline said in a statement Wednesday.

Alaska is inspecting its aircraft for safety under guidance from the National Transportation Safety Board. The airline said it is also awaiting instructions on how to fix planes with problematic hardware. The planes will only be returned to service when they "meet all FAA and Alaska's stringent standards," according to Alaska Airlines. 

Passengers whose flights are cancelled or significantly delayed are entitled to full refunds under airline policy and federal law.

"We hope this action provides guests with a little more certainty, and we are working around the clock to reaccommodate impacted guests on other flights," the carrier said.

Alaska Air's fleet includes 65 737 Max 9 aircraft. Of those, 18 recently had full inspections, including of the door plugs, and have since been cleared to return to service, according to the carrier.

Boeing CEO Dave Calhoun told employees of the aviation company on Tuesday that the company is "acknowledging our mistake" in connection to the potential tragedy involving the Alaska Air plane. 

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Megan Cerullo

Megan Cerullo is a New York-based reporter for CBS MoneyWatch covering small business, workplace, health care, consumer spending and personal finance topics. She regularly appears on CBS News streaming to discuss her reporting.