In early trading on Wall Street, Lockheed Martin ( NYSE:LMT ) Corp was down 0.3% at US$356.83, while Raytheon ( NYSE:RTN ) Technologies Corp dropped 1.5% to US$85.97 and Northrop Grumman ( NYSE:NOC ) Corp dipped 0.8% to US$360.34. READ: Boeing-Airbus dispute between US and EU resolved after 17 years Other firms with large defence operations were also on the decline, with Boeing Co ( NYSE:BA ) sinking 2.6% to US$228.30 while General Dynamics ( NYSE:GD ) Corp slipped 0.3% to US$197.72.