Boeing has predicted a “mid-2020” return to service for the 737 Max, months later than anticipated.

Trading was halted in Boeing shares following release of the news, with the price having fallen five per cent earlier.

While emphasising safety remains the priority, Boeing said in a statement: “We are informing our customers and suppliers that we are currently estimating that the ungrounding of the 737 Max will begin during mid-2020.

“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.”

The plane type has been grounded since March last year following two fatal crashes.

Lion Air flight 610 was lost in Indonesia in October 2018, killing 189 passengers and crew.

The incident was followed by the downing of Ethiopian Airlines flight 301, with the loss of all 157 people aboard, in March 2019.

Following the second incident, global authorities banned commercial operation of the 737 Max.

After initially predicting a speedy return for the plane, Dennis Muilenburg was replaced as chief executive of Boeing as the grounding approached its first anniversary.

Boeing halted production of the aircraft earlier this month, with as many as 400 planes already awaiting delivery.

The American giant has been working with the FAA and other aviation authorities to recertify the plane for commercial operation.

Boeing added: “Returning the Max safely to service is our number one priority, and we are confident that will happen.

“We acknowledge and regret the continued difficulties that the grounding of the 737 Max has presented to our customers, our regulators, our suppliers, and the flying public.”

The company is expected to provide additional information about the return to service of the plane alongside quarterly financial disclosures next week.