WASHINGTON: A California-bound Alaska Airlines flight made an emergency landing shortly after taking off from Portland, Oregon, after a window reportedly blew out, according to media reports.

The Boeing 737-9 MAX took off at 4.52 p.m. on Friday evening and returned to Portland 20 minutes later, Xinhua news agency reported.

According to photos sent in by a passenger, a large part of the airplane's fuselage and a window was missing.

The Alaska Airlines Flight 1282 returned safely to Portland International Airport after “the crew reported a pressurization issue”, CNN quoted the Federal Aviation Administration (FAA) as saying.

Both the Portland International Airport and Alaska Airlines confirmed the emergency landing.

Alaska Airlines also confirmed that an incident happened on Flight 1282, which was headed from Portland to Ontario, California.

“The aircraft landed safely back at Portland International Airport with 171 guests and six crew members,” the airline said.

We are investigating what happened and will share more information as it becomes available.”

Kyle Rinker, a passenger on the flight, told CNN that a window popped off shortly after takeoff.

“It was really abrupt. Just got to altitude, and the window/wall just popped off and didn’t notice it until the oxygen masks came off,” he added.

The FAA and National Transportation Safety Board have announced that they will investigate the incident.