Boeing has said it still does not know how the crisis over the safety of its 737 Max 8 jets will affect its profits.
In its latest set of results, Boeing said that due to the uncertainty over when the plane would be allowed to fly again, it could not forecast profits for this year.
A fall in 737 deliveries has already led to a $1bn drop in revenues.
In March a Max 8 belonging to Ethiopian Airlines crashed, killing all 157 passengers and crew.
It was the second crash involving a Max 8 jet in five months. The two disasters prompted aviation regulators to ground the aircraft.
“Due to the uncertainty of the timing and conditions surrounding return to service of the 737 Max fleet, new guidance will be issued at a future date,” Boeing said in its first quarter results.
Boeing’s commercial aircraft division managed to offset the impact of the Max 8 groundings by increasing sales of its 787 planes. Even so the division still saw a 9% fall in revenue to $11.8bn from $12.9bn.
Boeing’s core operating earnings in the first three months of the year were 21% lower at almost $2bn, reflecting a one-third drop in deliveries of the Max 8.