Sen. John McCain is demanding information from Pentagon leaders on an over-budget aircraft carrier and ill-fated missile-defense system.

McCain, ranking member of the Senate Armed Services Committee, sent related letters recently after firing off additional budget-related missives to the Pentagon over the past week.

He addressed the Medium Air Extended Defense System (MEADS), a three-nation program the United States had planned to stop participating in, in a letter to Defense Secretary Leon Panetta.

The FY ’12 defense authorization act that Congress passed last December says the Pentagon cannot spend more than 25 percent of its $390 million in funding for the year until the defense secretary reports on plans to either terminate or restructure the program.

McCain said he is “disappointed” the Pentagon “has chosen to ignore current law and congressional direction by requesting an additional $400 million for MEADS in fiscal year 2013 to continue the ‘proof of concept’ that Congress instructed be completed utilizing no more funding than the level appropriated for fiscal year 2012.”

The senator said he also is concerned by Panetta’s recent remarks pledging to do “everything possible” to obtain congressional support for the additional MEADS funds.

McCain said the SASC determined last year that “further taxpayer resources should not be wasted on persistently underperforming multibillion-dollar development efforts, such as MEADS, that will not result in the procurement of commensurate capability directly benefitting the warfighter.” He called for the Pentagon to negotiate with partners Italy and Germany to kill MEADS or limit it to fit within the FY ’12 funding.

He wants the defense secretary to explain how the Pentagon’s MEADS FY ’13 funding request jibes with the FY ’12 law, and how the Pentagon will comply with that authorization measure for the current fiscal year.

McCain also wrote to Navy Secretary Ray Mabus recently requesting data on the USS Gerald R. Ford (CVN-78) aircraft carrier. The cost, he said, has grown to more than $12.3 billion, or an increase of 18 percent in less than four years and $500 million over the congressionally mandated cost cap. He had previously quizzed Mabus about the Navy’s plans for controlling the ship’s costs at a March 19 SASC hearing.

He told Mabus in the letter he was “underwhelmed” by the Navy secretary’s “recitation” at the hearing of measures the Navy has already taken and its plan to apply lessons learned from CVN-78 while building the next carrier, CVN-79.

“Not only have your actions to date failed to control cost growth in this $40 billion program, it appears that you do not now have a plan to prevent future increases,” McCain charged. “Failure to effectively manage a program of this size and importance at a time of growing pressures on the defense budget raises serious questions about the viability of the aircraft carrier program and will cut into funding not only for other shipbuilding programs, but potentially for other defense priorities. “

McCain told the Navy to craft a plan by April 13 detailing specific steps it will take to “drive affordability” into the CVN-78 effort and ensure costs are controlled with CVN-79 and CVN-80. The senator said that data will inform the SASC’s consideration of the Navy’s $608 million FY ’13 request for CVN-79 construction as well as requests to reprogram funds and garner relief from the congressional cost costs.