Those tiny platforms would still be bouncing on every density change AKA "airpocket" even if they hold a stead course.It helps that the drones are flying in a straight line. They do not autonomously engage in dogfighting like a WWI. It's being able to intercept, get up alongside and put a few rounds through it....and not shoot down other helicopters doing the same.
Still four or five helicopters chasing a dozen or two of drones is probably going to miss a couple.
Another option is suicide drones: drones built to intercept and crash into another drone. These drones would be lighter and faster since they won't be carrying an explosive payload even if exactly the same type of drone. They'd be cheaper than Patriot missiles.
Now I'm no drone pilot or programmer but I'd bet they are autocorrecting their course constantly since they probably run off GPS and if they are piloted then all bets are off.
Don't get me wrong, I'm not trying to shoot your post fulla holes I'm just adding my thoughts.