Boeing said it could stop production of the 737 Max aircraft after the company reported losses of $2.9bn in the three months to the end of June.
It is the largest ever quarterly loss and follows two crashes involving the 737 Max plane.
In comparison, Boeing reported a profit of $2.2bn for the same period last year.
Chief executive Dennis Muilenburg said production of the plane could be slowed or halted if regulators do not move to lift the ban on the 737 Max, which was the company’s best-selling aircraft.
The entire fleet was grounded in March after crashes in Indonesia and Ethiopia.
More: Boeing 737 Max ‘could be grounded until new year’
Boeing pledges $100m to 737 Max crash victims
Special Report: Boeing MAX-ed out by disasters
Boeing had predicted the Max would fly again by the end of the year.
But on Wednesday, Muilenburg said the company may have to consider slowing or halting production if there are further setbacks.
“We might need to consider possible further rate reductions or other options including a temporary shutdown of the Max production,” he said.
The fatal crashes involved a Lion Air Max in Indonesia and an Ethiopian Airlines flight in Ethiopia that claimed a total of 346 lives.
A $100m fund is being established to compensate the families and communities affected by the crashes.
“This is a defining moment for Boeing and we remain focused on our enduring values of safety, quality, and integrity in all that we do, as we work to safely return the 737 Max to service,” Muilenburg said.
“During these challenging times, teams across our enterprise continue to perform at a high level while delivering on commitments and capturing new opportunities driven by strong, long-term fundamentals.”
More: Boeing 737 Max ‘could be grounded until new year’
Boeing pledges $100m to 737 Max crash victims
Special Report: Boeing MAX-ed out by disasters
