Alaska Air returns 737 MAX 9 involved in mid-air blowout to Boeing Alaska Airlines said on Friday it has returned to Boeing the 737 MAX 9 plane that in January was involved in a mid-air door panel blowout. U.S. investigators on Thursday sanctioned Boeing for revealing details of a probe into the blowout and said they would refer its conduct to the Justice Department, prompting the planemaker to issue an apology.