"How in the hell do you lose an F-35?" wondered Rep. Nancy Mace, the South Carolina Republican, in a post on social media Sunday that speaks for everyone who read the headline about the state-of-the-art military plane that went missing earlier in the day. A more general ... question could be asked of the F-35 program: How in the heck can you spend so much money on a plane that doesn't work the way it's supposed to? The exact amount of money for a single aircraft like the one that went missing is somewhere around $100 million. The entire F-35 program is on track to cost $1.7 trillion. The Project on Government Oversight, a nonpartisan watchdog group, has written extensively on the F-35 and its cost overruns. I asked Dan Grazier, an F-35 expert for POGO, what has gone wrong. It all boils down to "failure at the conceptual level," he told me in an email. "The architects of the program attempted to build a single aircraft to meet multiple mission requirements for not just three separate services but also those of multiple countries," Grazier said. The jet has never reached its full operational capability and already needs updates and tweaks, including a new engine. "Every F-35 built until now is nothing more than a very expensive prototype," Grazier told me. The Government Accountability Office ... earlier this year described the F-35 program as "more than a decade behind schedule and $183 billion over original cost estimates."