American Airlines pilots have warned that Boeing Co.'s draft training proposals for the troubled 737 Max do not go far enough to address their concerns, according to written comments submitted to the U.S. Federal Aviation Administration and seen by Reuters.

The comments were made by the Allied Pilots Association (APA), which represents pilots at American Airlines Group Inc., the world's largest airline and one of the biggest 737 Max operators in the United States.

Their support is important because Boeing has said pilots' confidence in the 737 Max will play a critical role in convincing the public that the aircraft is safe to fly again.