The U.S. defense industry may be heading for its worst year for new orders and exports out of the past four. Year-to-date the State Department has approved $42.3 billion of exports of military aircraft and weapons systems vs. $57.3 billion at the same stage last year, and below the same point in 2015 and 2014. Aerospace has done better than weapons and vehicles with a 50.6% increase in orders approved vs. a 68.4% slump. The latter is being felt in the short-term with a 35.0% drop in exports of weapons and vehicles in the third quarter on a year earlier. The impact of higher aircraft orde...