The Defense Department on Tuesday announced an agreement in principle to buy 71 more F-35 fighter jets from Lockheed Martin at somewhat lower prices than last year. http://www.nytimes.com/2013/07/31/business/pentagon-buys-71-more-f-35s-from-lockheed-martin.html?ref=us  People briefed on the latest deal, which includes ancillary equipment, said it was worth more of what is by far the Pentagon’s largest program, which could cost $392 billion for than $7 billion. After years of delays and cost overruns, military officials have been under pressure to reduce the cost more than 2,400 planes.