The manager oversaw pilots whose messages have embarrassed the aerospace giant as it struggles to get the 737 MAX flying again

Boeing Co. has fired a midlevel executive in charge of pilots who exchanged internal emails that have embarrassed the aerospace company as it struggles to get the 737 MAX jetliner flying again, according to people familiar with the matter.

The ouster of the executive, Keith Cooper, follows the disclosures of the messages between two Boeing pilots that prompted concerns among federal lawmakers and regulators that some of the company's employees took a cavalier attitude toward safety and honest communication with airline customers.

The messages also involved other Boeing employees.

Mr. Cooper was a vice president for training and professional services in Boeing's global-services division, the people familiar with the matter said. His departure hasn't been previously reported.

Mr. Cooper couldn't be reached for comment. Mr. Cooper departed the company within the past couple of months, one of these people said.

Mr. Cooper didn't send or receive the messages, the latest batch of which Boeing disclosed to lawmakers and the news media in January, this person said. Those messages show Boeing employees mocking airline officials, aviation regulators and even their own colleagues. In one, an employee said the 737 MAX had been "designed by clowns, who in turn are supervised by monkeys."

Boeing Chief Executive David Calhoun, who has called the messages "totally appalling," has said he aimed to stamp out such behavior and hold managers accountable. "Awareness in the leadership ranks around whether that's happening or not is not an excuse if it's happening," Mr. Calhoun said in a call with reporters in January, shortly after taking over as CEO. "Disciplinary actions have to be taken."

Boeing leaders have faced questions from federal lawmakers about who has been held accountable for the MAX crisis. The aircraft has been grounded since last March, after two fatal crashes that claimed 346 lives.

Boeing previously reassigned a company pilot, Patrik Gustavsson, from an important 737 MAX role after congressional investigators in October disclosed messages in which his then-colleague suggested having misled regulators.

In a 2016 instant-message exchange, Mr. Gustavsson and Mark Forkner, who was then the MAX's chief technical pilot, appeared to discuss modifications to a MAX flight-control system that was later implicated in both fatal crashes, comparing notes on flight-simulator problems. At one point Mr. Forkner said: "So I basically lied to the regulators (unknowingly)."

In his role as chief technical pilot, Mr. Gustavsson had been responsible for working with airlines and regulators on crew training and pilot manuals for the aircraft. He still works at Boeing, now as a production pilot whose responsibilities include working with finished airplanes, people familiar with the matter said. Boeing declined to make him available for comment.

Mr. Forkner's attorney has said his client was referring to problems with the simulator, not the flight-control system itself. Mr. Forkner left Boeing to work at Southwest Airlines Co., a major MAX customer. Southwest CEO Gary Kelly said in October Mr. Forkner's messages weren't related to his current job and that the pilot was by all accounts a "very fine man and does a fine job for us."

The cadre of technical pilots Mr. Cooper once oversaw is the same group now poised to work with the Federal Aviation Administration's pilot-training specialists to develop ground-simulator training programs before the MAX fleet can return to service.

Some senior executives have moved on. In October, Boeing ousted Kevin McAllister, then its commercial-airplane division chief. In December, the company's board removed Dennis Muilenburg as CEO after a series of setbacks and overoptimistic assumptions related to winning regulatory approval.

Others have retired or shifted to other projects at Boeing.

Keith Leverkuhn, who oversaw the 737 MAX's development as the program's general manager, is now a vice president for propulsion systems in the company's commercial-airplane division.

Michael Teal, the program's chief engineer during the MAX's development, is the top engineer for Boeing's newest and most important current airliner under development, the long-haul 777X, which took its first flight last month.

Mike Sinnett, a senior engineer who had been Boeing's point person with regulators, pilot groups and the media on Boeing's efforts to fix the MAX, is focusing on developing new Boeing aircraft. He also is a member of a high-level, federally sponsored advisory committee advising regulators about drone safety.

Boeing estimates regulators will approve the MAX to resume commercial service by midyear, a step that will allow the company to start reintroducing the 385 planes parked by airlines world-wide. Then it will start delivering just over 400 more completed planes being stored in Washington state and Texas.

The plane maker's overall first-quarter deliveries of other plane types could also decline because of a slump in demand related to the coronavirus outbreak, Chief Financial Officer Greg Smith said at an investor conference Wednesday. Chinese airlines have cut flying by as much as 70%, aircraft lessor Avolon said this week.