Boeing has announced it is going to suspend production of its grounded 737 MAX planes in the new year.
The model has not flown for nine months after two separate crashes killed more than 300 people.
Boeing has been working to update the plane's software, and aviation regulators will need to give the plane permission to fly again.
However, with the process taking "longer than expected", Boeing now says it will focus on delivering stored aircraft and halt production on the planes.
The aircraft manufacturer says it will not be laying off any of its workers, and staff for now will be temporarily reassigned to other teams.
In a statement, the aircraft manufacturer said: "Throughout the grounding of the 737 MAX, Boeing has continued to build new airplanes and there are now approximately 400 airplanes in storage.
"We have previously stated that we would continually evaluate our production plans should the MAX grounding continue longer than we expected.
"As a result of this ongoing evaluation, we have decided to prioritise the delivery of stored aircraft and temporarily suspend production on the 737 program beginning next month."
The firm says it will provide information about the financial impact of the production suspension in an earnings report next month.
However, the decision is expected to significantly impact suppliers, airlines and financiers across the globe.
The ongoing grounding of the 737 MAX fleet has already led to airlines such as Ryanair cutting their growth forecasts.
Boeing has been working on software revisions to the MAX planes in the wake of the two crashes in October 2018 and March 2019.
189 people died in the Lion Air crash off the coast of Indonesia, while 157 were killed when the Ethiopian Airlines plane came down shortly after take-off.