Boeing share tumbled Friday morning after WSJ reported production for the 787 Dreamliners has "slowed" to address defects in the planes. This further complicates deliveries to carriers that may face delays of the new American wide-body jet airliner. 

Sources told WSJ that Boeing is holding off completing new 787 Dreamliners at its North Charleston, South Carolina facility as engineers address problems related to passenger and cargo doors on aircraft already under construction. 

The production slowdown began earlier this week and could last as much as two weeks as Boeing works to address the door issue. 

Shares of Boeing slumped more than 4% as of 1027ET.