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 US Federal Aviation Administration and seen by Reuters.

Boeing Co on Wednesday abandoned its 2019 financial outlook, halted share buybacks and said lowered production due to the grounding of its fastest-selling 737 MAX jet after two fatal plane crashes in five months had cost it at least $1 billion so far.

Boeing Co said it invited more than 200 global airline pilots, technical leaders and regulators for an information session on Wednesday as it looks to return the 737 MAX to commercial service.