Dear Peter,
As to "any other candidates"? I nominate: the Lafayette Escadrille. I apologize, but I won't be naming names here, out of a respect for the dead...
But, the fact is, having read their biographies in Gordon's THE LAFAYETTE FLYING CORPS (Schiffer, of course!), I concluded that, in more than one instance, I would not have wanted to fly with some of these gentlemen (which they were, by American standards of the time, almost all having come from Ivy League backgrounds-- our own "playing fields of Eton").
Let me clarify-- I'm talking about two or three fliers who were a liability to the Escadrille to the point of putting their squadron mates' lives in danger. The type of "young Turk" who would break formation, abandoning the mission objective, because he saw a German plane nearby. No discipline whatsoever; "loose cannon" might be a good term...
Please don't interpret the above to mean Lufbery (or Bert Hall, for that matter). Luf was his own special case-- a man driven by an all consuming desire for vengence (I assure you, I'm NOT exagerrating)-- but he did not place others in danger in his drive (lust?) to destroy Germans...
I WAS surprised by your comment on Ball, for I know that you have already read Libby's
HORSES DON'T FLY, in which Ball comes across as a dedicated, competent, even patient airfighter. I still can't get over the image of Libby first meeting Ball while the latter was playing tennis. It reminded me of Drake's bowling...