"When you breach the trust of the American people with that safety and with your manufacturing, we're going to put the screws to you to make sure you change your ways and start doing things right," Duffy told Fox News after a visit to the Boeing 737 factory in Washington.

Duffy also confirmed that the Federal Aviation Administration isn’t yet prepared to lift the current restriction limiting Boeing’s (NYSE: BA) 737 Max production to 38 planes a month, Reuters reported.