The top U.S. military officer has opened the door for cuts to the troubled F-35 fighter jet program.

Army Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, says developing and building three variants of the high-tech fighter creates fiscal challenges for the department.

He is telling the House Armed Services Committee that he is committed to developing a new, fifth-generation fighter. But he is questioning whether the U.S. can afford separate versions for the Air Force, Navy and Marine Corps.

The F-35 Joint Strike Fighter is the biggest weapons procurement program for the Pentagon, costing $238 billion. The program is plagued with delays and cost overruns, and one variant of the plane suffered cracks in the bulkhead after it flew just 1,500 hours out of a planned 16,000.