The aircraft is currently expected to return to the air in January 2020, 12 months after the company proposed the initial replacement of software implicated in two deadly crashes, Xinhua news agency quoted US Federal Aviation Administration (FAA) officials and industry leaders as saying on Sunday.
Boeing executives, FAA engineers and global aviation regulators have extended the safety analyses to cover a growing list of almost all the issues from emergency recovery process to potentially suspect electronic components.
The Wall Street Journal on Sunday quoted officials at the FAA and pilot-union leaders as saying that no firm timeline has been established but one scenario anticipates the plane could return to the air in January 2020.
American Airlines have already extended its ban on Boeing 737 MAX flights through November 2, the company said on Sunday in a statement, right after United Airlines announced its decision to keep Boeing 737 MAX flights out of schedule until November 3.
American Airlines' announcement on Sunday marked the fifth time that it has pushed back the expected time that the MAX would resume flying.
The airline had previously announced on March 24 that it was extending its cancellations through April 24.
The Boeing 737 MAX was grounded worldwide following the deadly crashes of Lion Air Flight 610 in October 2018 in Indonesia and Ethiopian Airlines Flight 302 in March this year that killed a total of 346 people.
( With inputs from IANS )