WASHINGTON — A report from the Pentagon’s internal watchdog strongly criticizes managers and workers at Lockheed Martin’s Fort Worth plant, which makes the F-35 fighter jet, saying a lackadaisical attitude has led, on average, to more than 200 repairs for each aircraft and has cost taxpayers millions.The Pentagon’s Office of Inspector General, which assesses the department’s performance from within the massive federal agency, also criticized two internal Defense Department offices responsible for overseeing the F-35 project, saying their oversight has been weak to nonexistent.“Lockheed Martin’s Fort Worth, Texas, quality-management system and the integrity of the F-35 product are jeopardized by a lack of attention to detail, inadequate process discipline and a ‘we will catch it later’ culture,” the report concluded. “We believe the quality-assurance culture at [the F-35 plant] must improve and that robust technical oversight by the government is required to ensure program performance and mission success.”Lockheed Martin downplayed the report, saying it is based on old data and that problems are being resolved.Joe DellaVedova, Pentagon spokesman for the F-35 program, said Wednesday that the cost of each fighter jet is dropping, from $133 million last year to a projected $112 million in 2015, as problems are ironed out and full production is reached in 2018.“We haven’t reached full-rate production,” DellaVedova said. “We’re still following a learning curve.”The F-35, formally called the joint strike fighter, has encountered many design and production difficulties since it was first conceived as the U.S. military’s fifth-generation stealth aircraft more than a decade ago. Its original $400 billion price tag has doubled, with critics predicting more increases.“The F-35 is now the first $1 trillion weapon system in history – a consistent series of cost overruns that have made it worse than a disgrace,” Sen. John McCain, R-Ariz., said last month at a Senate Armed Services Committee hearing.Partly in response to such criticism from lawmakers, Pentagon and congressional investigators, and outside watchdog groups, Lockheed Martin announced a new management team in March for its aeronautics division. The Joint Program Office, the Pentagon agency that oversees the F-35 project, has also overhauled its leadership.During a June visit to Fort Worth, two top Pentagon officials said that the working relationship with Lockheed was improving and that they were cautiously optimistic that production could be increased.During a 13-month probe of the troubled project, which is the largest U.S. weapons acquisition program ever, the Defense Department inspector general found 70 problems at the Lockheed factory in Fort Worth, identifying 28 of them as major. It found 119 other major issues at Lockheed’s five main subcontractors’ plants in the United States and Britain, including the United Technologies factory in Fort Worth, where the F-35 landing-gear systems are being made.“Identified issues could adversely affect aircraft performance, reliability, maintainability and ultimately program cost,” the inspector general said.Lockheed Martin said the report relied on outdated information and described problems that have been resolved.“This report is based on data that’s more than 16 months old, and the majority of the Corrective Action Requests have been closed,” the company said in a statement.