Five years ago, the Pentagon was on cusp of an air-combat revolution. For a few brief, heady months in late 2005, it looked like the U.S. military might soon launch full-scale development of a new class of fast, lethal Unmanned Aerial Vehicles eventually capable of replacing all kinds of fighter jets, from the older F-15s, F-16s and F-18s to the latest F-22s.

But the revolution fizzled when the Air Force abandoned its share of the so-called Joint Unmanned Combat Air System effort. Manned jets continued to dominate, culminating in today’s mammoth, $300-billion F-35 program.