Boeing Co. /zigman2/quotes/208579720/composite BA -2.08% said Tuesday it expects that its 737 Max jets will start to return to service "during mid-2020." Boeing shares were halted ahead of the announcement, when they were down 5.5%. "This updated estimate is informed by our experience to date with the certification process. It is subject to our ongoing attempts to address known schedule risks and further developments that may arise in connection with the certification process," Boeing said in the statement. That timeline "also accounts for the rigorous scrutiny that regulatory authorities are rightly applying at every step" of their review of the 737 Max's flight control systems and future pilot training requirements, the company said. The 737 Max jets have been grounded since March after two deadly crashes less than five months apart, and the company has been mired in criticism for the way it handled the plane's certification and further missteps in the recertification.