"The Department of Justice will not tolerate fraud – especially in industries where the stakes are so high," the agency said.
The airline said safety remained its “highest priority” and that it was working closely with federal investigators.
Officials believe they have identified the location of the flight data recorder and cockpit voice recorder, one day after the passenger plane carrying 62 people crashed.
American Airlines ferried passengers from Miami to New York on the first flight.
The nation’s air safety agency allows the jet to resume flying after two years of review since a pair of deadly crashes.
Boeing astronaut Chris Ferguson said it was a difficult decision, but said he has several commitments “which I simply cannot risk missing.”
The Transportation Committee issued the scathing report Wednesday following an 18-month investigation into two deadly 737 Max jet crashes.
The return of the company's top-selling aircraft, which has been grounded since March, was originally supposed to happen much sooner.
Dennis Muilenberg was replaced after a year of controversy that included the grounding of Boeing 737 Max jets.
The crew capsule, which was built for NASA, had ended up in the wrong orbit after its launch on Friday because of an issue with the spacecraft's internal clock.
A protesting Santa, a rescued orangutan and a walking Christmas tree are some of this week's best images.
The company has no immediate layoffs planned when the production freeze goes into effect in January.
Boeing said Wednesday that John Hamilton planned to retire last year as chief engineer of commercial airplanes, but he stayed on to help get the Max back into service.
A flight-control system pushed the nose of two 737 Max planes down before crashes that killed 346 people.
After 346 deaths, Dennis Muilenburg faced tough questions on why more wasn't done to address safety concerns about the plane.
Lion Air flight 610 crashed because pilots weren't told how to quickly respond to malfunctions in Boeing 737 Max 8 jet’s automated flight-control system.
The pilots claim they lost $100 million in wages when Boeing was forced to ground the jets following two fatal crashes.
The reported complaint said management was more concerned with costs and keeping the Max on schedule than on safety.
Pentagon didn't factor in $1.6 billion discount Trump claimed he negotiated.
United, American and Southwest have taken Boeing's Max off its schedules through fall as uncertainties over the jets persist.