FredEx was at Delta as president of DCI, then Delta says that DCI is redundant, eliminates it, and demotes him to Comair CEO. A year later FredEx leaves Comair because CVG is too far from ATL and he doesn't want to move his family. Then he takes a job in Wyoming .

So Delta names UncaDon as CEO of Comair. He takes Comair through the gristmill and gets promoted to head of the new DCI, because Delta thinks that would be a good position to have.

Right now anything would make sense to Delta.