WASHINGTON (Reuters) - Lockheed Martin Corp’s F-35 fighter jet program is essential for the security of the United States and its allies, a Pentagon official said on Monday, looking to defend the program a week after President-elect Donald Trump criticized it for delays and cost overruns. “The F-35 program and cost is out of control,” Trump wrote on Twitter last week, echoing campaign promises to cut waste in federal spending. “Billions of dollars can and will be saved on military (and other) purchases after January 20th.” Speaking with reporters on Monday, Air Force Lieutenant General Chris Bogdan, who runs the F-35 program for the Pentagon, said that if he had an opportunity to speak with the Trump transition team, he would tell them that the program is now under control after years of delays. “There is a perception that this program is out of control,” Bogdan said. “So, if given the opportunity I would like to try and explain to the new administration that this is a vastly different program from 2011.” Bogdan said the incoming administration was trying to get industry and the Defense Department to get a better value for its money. “I applaud the new administration for that, because that is what we should all be striving for,” he said. Trump’s Twitter broadside sent defense shares tumbling and fanned concerns that the incoming administration will reduce defense contractors’ profit margins and cut broader federal spending, threatening U.S. factory jobs even as Trump promises to boost manufacturing employment. The F-35 program, which has been described as the most expensive weapon system in history, has been dogged by problems, with the Pentagon’s chief arms buyer once describing as “acquisition malpractice” the decision to produce jets before completing development.     