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 uncertainty over when the plane would be allowed to fly again meant 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 round the world to ground the aircraft.
“Due to the uncertainty of the timing and conditions surrounding return to service of the 737 Max fleet, new guidance [on profits] will be issued at a future date,” Boeing said in its first quarter results.
Boeing is temporarily cutting production of the 737 airliner from 52 planes a month to 42 from this month.
Despite the drop in production Boeing has not laid off staff and is maintaining order levels with many suppliers, all of which is keeping costs high. Meanwhile, some 50 deliveries of new 737 Max planes have been withdrawn.
