One of the earliest stealth weapons on record was a stone used by the young Israelite David to kill the Philistine giant Goliath. In the biblical account, David shunned the conventional armaments of his time: sword, helmet, armor. Instead, he went forth with a slingshot and a few stones, kept undetected in a pouch. As any schoolchild knows, one well-aimed fling was all it took to put Goliath down for good. The big guy never saw it coming.

It is not clear to what extent David tested his weapon before doing battle, but he presumably had experimented. The first Book of Samuel tells how he had earlier struck and killed a lion and a bear that menaced the sheep he tended.

In a sense, not much is different with today’s far more sophisticated arsenals; development and testing remain essential. Only the costs and the stakes are considerably higher now, as is made evident in this latest offering from the video documentary producers of Retro Report, who have focused on a supersonic stealth plane called the F-35 Joint Strike Fighter. While still a work in progress, it has already become the most expensive weapons project in military history.

By the time the F-35 program is fully up and running — with an American fleet of more than 2,400 planes planned by the late 2030s — projected total costs will exceed $1 trillion. One billion dollars will be needed just to pay for the highly advanced pilot helmets, running to $400,000 apiece. And though champions of the supersonic F-35 hail it as the ultimate sky fighter for the 21st century, skeptics ask if it is worth all the money and effort, or even if it will prove as effective in its mission as David’s little stone was in its day.