The world's largest plane maker Boeing Co (BA.N) said on Friday the U.S. Federal Aviation Administration had officially certified its 737 MAX-9 aircraft for commercial service.

The stamp of approval affirms the airplane's handling, systems and overall performance all comply with required aviation regulations, Boeing said.

Keith Leverkuhn, 737 general manager, said on Wednesday he expected the certification "within a matter of days-weeks."

Boeing said it was in the final stages of preparing the aircraft, which is designed for 220 passengers, for its first delivery to Lion Air Group.