[namesakes]

Yeah, maybe it isn't easy to make the AI distinguish "aggressive behaviour", or even do good visual ID. But how's this for a use case: Simply declare a restricted airspace, where every plane needs to have transponder replying correctly to some challenge-response authentication protocol. Distribute transponders to allies. Tell about zone in the evening news, so that everyone knows. Then program drones to shoot down anything that doesn't respond correctly. I'm pretty sure that it's a lot cheaper to design and build drone with same performance characteristics as top A2A fighter, there's so much that you don't have to worry about: human rating everything (you don't have to make so damn sure that everything works without the hitch first time), all the control systems that you have to build the pilot an interface to (radar, etc.), the cocpit.. I'm sure those will easily pay for developing a competitive fighting-AI.