Loitering in the sense of expending fuel load until a hypothetical target arrives? Or loitering in the sense it's there for reconissance and isn't intended to directly destructively interact with the target?

There's a big difference between a Predator with Hellfires, a tomahawk, A Global Hawk, or a man portablerecon/kamikaze drone, and finally Project Pluto, the ultimate "F you" device likely ever contemplated.