There's a saying that drone warfare enthusiasts keep reinventing the guided missile. Proponents point out that drones are cheap and disposable compared to the value of the targets they attack. But a drone can travel further, faster, and with more armor and ordinance if it doesn't carry fuel to return or equipment to land.

The problem with missiles is that they have a limited amount of propellant. Most missiles will spend the majority of their flight time gliding toward their target after the initial boost phase. Fighters can spend hours in the sky, and fly thousands of miles away from their home base. Missiles are limited to a range of several hundred miles and a few minutes max, even with advanced loitering technologies.

If it's loitering, or intended to come back, it isn't functionally a missile.

And why in the hell would you fire a missile without a target that would require it loiter unless you were doing something completely mad like Project Pluto? That just doesn't really make sense at all. Though it reminds me of a torpedo from a Michael DiMercurio book that had to be sedated due to it's carbon based computing matrix being smart enough to basically guarantee a hit on an enemy combatant submarine, but not smart enough to understand IFF.

Loitering missiles are excellent at destroying targets of opportunity; a radar site that is only active temporarily, a convoy of armor moving from its lager, etc etc etc.

Isn't that what a Predator/Reaper is for? Maybe I'm lacking imagination, but a loitering missile seems very difficult to make.