MARNIE HUNTER AND FORREST BROWN, CNN January 10, 2024 at 1:29 PM

A terrifying Alaska Airlines incident on Friday that left a hole in the side of a Boeing 737 Max 9 aircraft shortly after takeoff from Portland, Oregon, has raised safety questions and put many would-be air travelers on edge. Investigators are looking closely at the failure of a mid-cabin door plug that detached during the flight, leading the Federal Aviation Administration to ground all US 737 Max 9 aircraft that have the door plug feature until the aircraft can be thoroughly inspected.