The 2021 settlement angered the crash victims’ families, who have long argued that Boeing and its executives should face greater consequences, including a public trial. Many of those families have reached civil settlements with the company, though a handful are pursuing civil damage trials that are scheduled to begin late this year.

In 2022, a jury in Texas acquitted a former Boeing technical pilot, Mark A. Forkner, of defrauding two of the company’s customers, in the only criminal case the federal government brought against an individual connected to the crashes.

The Justice Department has also opened a criminal investigation into Boeing over a January flight, in which a panel blew off a Max jet operated by Alaska Airlines. No major injuries were reported, but the incident reignited concerns among lawmakers and the public about the quality of Boeing jets.

The company has since announced a series of changes, including expanded training, simplified plans and procedures, and better quality control when it comes to supplier parts. As part of that effort, Boeing plans to buy a troubled supplier, Spirit AeroSystems, which makes the bodies of its 737 Max and 787 Dreamliner planes.

The appointment of a federal monitor as part of the plea deal represents a possible rebuke of the F.A.A., which oversees Boeing. The agency had been widely criticized for failures leading up to the crashes, including giving the company too much leeway to monitor quality and safety on the government’s behalf.

The F.A.A. has since adjusted its practices, limiting the circumstances in which it delegates its authority, and making a wide range of other changes. After the Alaska Airlines episode, the agency increased its presence at Boeing’s Max factory, limited the company’s output and imposed other restrictions on Boeing.

Mark Walker contributed reporting.