The head of the US Federal Aviation Administration (FAA), Steve Dickson, has signed an order permitting the grounded Boeing 737 Max to fly again.
Mr Dickson said he was 100% confident in the safety of the aircraft which was banned from flying after two crashes, in Indonesia and Ethiopia, which killed 346 people.
The FAA’s decision means the aircraft could return to the skies by the end of the year.
The FAA is calling for extra training for pilots to deal with new safety features installed on the airliner.
Boeing has welcomed the FAA’s move, saying it was committed to learning from its mistakes.