In The Force Awakens, we see two instances of starfighters shooting at ground targets. On Jakku, two TIEs try and fail to shoot the fleeing Finn and Rey. On Takadona, Poe Dameron shoots the stormtroopers guarding Han, Chewie, and Finn as he flies by.
Why was Poe's shot so much more accurate than the TIE's?
Was it purely pilot skill? This shouldn't be a factor, because of the advanced targeting computer systems and the extensive amount of training both pilots have received.
Was it because the TIE pilots were trying to hit moving targets? This is closer to correct, but it seems like the TIE's targeting systems, being designed for high-velocity space combat, should be able to account for this as well.
So what was the difference between the two? Why were the TIEs not even able to get Finn and Rey within the blast radii of their shots, while Poe was able to shoot at least one stormtrooper directly in the breastplate while engaged in an aerial battle?