Senators on Tuesday hammered the F-35 for its scheduling delays and cost overruns, but program officials said major problems are “behind us” and is largely moving forward on its new schedule.

Sen. John McCain, R-Ariz., and chairman of the Senate Armed Services Committee, criticized the program for delivering “no more than a trickle” of aircraft, far below original delivery estimates. At the outset, officials said they would have more than 1,000 F-35s by the end of the fiscal 2016. In reality, Lockheed Martin will have delivered just 179, McCain said.