The Pentagon is accelerating production of Lockheed Martin’s F-35 jet even though the planes are facing “significantly longer repair times” than planned: maintenance facilities are six years behind schedule. The time to repair a part has averaged 172 days -- “twice the program’s objective.” The shortages are “degrading readiness” because the fighter jets “were unable to fly about 22 percent of the time” from January through August for lack of needed parts. The Pentagon has said soaring costs to develop and produce the F-35, the costliest U.S. weapons system, have been brought under control, with the price tag now projected at $406.5 billion. But the GAO report raises new doubts about the official estimate that maintaining and operating them will cost an additional $1.12 trillion over their 60-year lifetime. Already, the agency said the Defense Department must stretch its resources to meet the needs of continued system development and production.