Boeing 737 MAX
The aircraft was grounded across the world three months ago after two fatal crashes.
"We have every confidence in Boeing and expect that the aircraft will make a successful return to service".
Boeing executives apologised to the families of those who died when 737 Max crashed in Indonesia and Ethiopia. The company said it was working hard to learn from what went wrong but didn't say when the plane could fly again. A total of 346 people were killed in both crashes.
Pilots of each plane struggled in vain to regain control over the automated system.
A faulty anti-stall system could have contributed to the disaster.
The firm's shares plunged more than 8% as probe into fatal crashes continues.
The German-based firm owns 15 of the planes, including five within its UK operation.
Two black boxes from the aircraft are being taken to Paris for investigation.
He said the safety of the American people is of “paramount concern”.
The move comes after the Ethiopian Airlines crash, which killed all 157 people on board.