I blame someone else for this idea.
I suggest that all drone combat aircraft be fitted with air-horns.
One toot means "take your hand off that RPG", two toots might be for "are you really sure you want to carrying that IED?" and so on.
Playing La Cucuracha indicates likelihood of imminent
Also running a drone is not free, so suggest it plays easy listening music with adverts from sponsors for example AK47-U-Like would probably be a good customer, which is probably less deleterious to the world than AKB-48 imho. See linky to candy advert, if you really must. Yes I definitely do live in the world centre for perv, lucky me, ne?
Could also serve a mobile phone antenna and wifi wossername, for a modest subscription, along with taking part in Amazon home deliveries.