From what I've read about the Great War, the pilots truly believed themselves to be Knights of the Sky, and successors to chivalric tradition and all of its codes. They wouldn't normally have gone at each other once the other was put out of action. There are umpteen stories of dogfights that ended when 1 pilot ran out of ammunition, and the other waved, saluted, and flew away, not willing to shoot an unarmed opponent. I'm sure that there were also cases of cold blooded killers like Beurling, who probably would've shot the bugger where he landed.
I don't think that I'd be able to kill a pilot like that.