The development of aircraft during the war made for exciting stories, but did they deliver any significant victories on either side?

The biggest impact wasn't flashy victories. Instead, the intelligence gained by photographic reconnaissance influenced nearly every battle of the war. Since you could get photographic proof of troop movements, artillery positions, and train movements you could know where the enemy was likely to hit next. As such, there was a nearly daily struggle to photograph the enemy's positions and at the same time prevent the enemy from photographing your own. This started nearly from the beginning of the war, when French planes confirmed the German advance and allowed effective resistance.

There was increasingly complex analysis of the photographs during the war, as the practice was basically invented during the conflict. Interpreting photographs advanced, with increasingly savvy interpreters being able to tease information out of the photographs. On the ground, the art of camouflaging things from the air also underwent rapid advances.

The practice of ground assault was also tried out, but its impact was less than decisive because the planes of the time were limited in the armor and armament they could carry for the job.

Comparing the impact of tanks and planes in WWI is tricky. Neither were decisive, but both were revolutionary. Planes spotted an attack even before it came, allowing reserves to be gathered and supplies to be stockpiled. Tanks allowed some advances to even exist. I would pick planes as being more important, mostly due to their longer service in the war. Then again, I am a military aviation nut, so take my opinion on this issue with a handful of salt.