The Washington Post reports the revolution in unmanned aerial flight has advanced quickly and in dramatic leaps, perhaps none more momentous than the historic landing of an autonomous Navy drone on an aircraft carrier. That happened for the first time two years ago, when Northrop Grumman’s X-47B, which looks more like a UFO than a military aircraft, took off and landed on the USS George H.W. Bush.It made history again last year, when it flew alongside F/A-18 fighter jets, the first time a drone flew in concert with piloted planes off a carrier. And later this month, the X-47B is expected to attempt what would be another aerial triumph: refueling midair by a tanker plane. But despite those breakthroughs, some powerful members of Congress and leading military think tanks say the Pentagon is being too cautious in its development of a technology that they think could push the boundaries of unmanned flight—and the future of warfare.