Boeing has informed its employees that the US aircraft manufacturer will set up a fourth 737 MAX assembly line at its widebody plant in Everett, adding to the three existing MAX assembly lines in Washington state.

Boeing last opened an advanced composite centre in Everett making 777X wings in 2016 and will now make use of the space freed up by ending the 747 and 787 production.

In a message to employees, Stan Deal, Boeing chief executive, cited the availability of highly skilled workers and factory space as factors in the decision, adding “this announcement underscores our commitment to the state and to Washington workers”.