Using guided mini-missiles might be a good idea. There are a few considerations to take into account though.
Flight correction time
Rocket-propelled grenades are pretty much bullet-fast. At that speed, there isn't much time to adjust the path of the missile as you're firing in close quarters. Planes dodging missiles is actually done IRL (though not at all like is depicted in the media) and as closer ranges with less time a miss would be guaranteed.
Have you heard a story from a guy who fired an RPG from inside a room? No, you haven't. When you launch an RPG or similar, there's a pressure wave from the back of the launcher called backblast, and it can kill people behind it. When you fire prone, you need to put it "sideways" across your shoulders so you don't wreck your legs.
And if fired in a confined space, the reflection of the backblast can kill the user.
Fortunately, there's a solution for both of these problems:
Make the micro-missiles slow. They launch out at maybe as fast as a fastball in baseball, so there's much less of an initial burst of air pressure to cause backblast, and it gives your fins more time to correct the speed. In addition, less power is needed to sustain a slower speed so that means a smaller rocket can be used.
This isn't too much of a concern. 25 mm grenades are a thing and your missiles, if the same size, will still pack a lethal punch. Note that you aren't going to have as many rounds as normal - the 25mm grenades for the XM25 airburst launcher came in 5-shot mags and your soldiers probably can't carry more mags than they could for other weapons with higher capacity.
Yield and damage
The most common idea with 25mm grenades is to use them to airburst around corners. You aren't going to get more of a yield than a grenade from these, since they'll use the same explosive as a grenade.
That said, you can specialize the payload for different targets. You can make anti-armor grenades for launchers, so your Hawks could use those against enemy armor.
As for taking out something like a helicopter, an anti-armor missile against the engine should work.
Something like a jet fighter, though... that's going to be hard simply because they're moving very fast. Good timing will be needed have the missile in the area where the plane will be, and you have to make sure that the plane doesn't just dodge. Unlikely, to say the least.