It used to be Comair Jet Express, and they are headquartered in CVG, right next to Comair's hq. The interview process used to be the same as Comair's, at least the Tech eval portion anyway. Delta changed the name and management, and now it's Delta's deal.
On a side note, I'm a bit suprized that this development has not caused the same furor as when United announced a corporate jet startup, separate from the airline. It seems the same to me, except that they purchased an existing one, quietly, as it was part of the purchase of Comair Airlines. Go figure.