Google showcased a radar-on-a-chip during the last IO; it looks exactly like something that could be fit onto a drone and provide short-range monitoring for incoming objects. The issue would be drone's reaction time though, especially when carrying heavy load.

As for hitting an intelligently-dodging vehicle - ever tried to throw a stick at a pigeon? I obviously don't recommend doing that, though I have some personal experience from the time when I was 9 years old, and I can tell you that suckers are damn good at avoiding projectiles. I doubt drones will reach that level of performance within next year or three, so for now, if you have something you could hit a pigeon with, you'll definitely be able to take a drone down with it.