"The highest unit revenues were reported by network carrier US Airways and regional carriers Comair and American Eagle Airlines.
Comair doesn't really have passenger revenue per se, they get paid by Delta, not the passengers. Even if the flight is empty, DAL pays the same as when it's full.
The bottom line is RJs are very expensive to operate on a per seat mile basis and that cost is paid by the network carriers. Comair receives a high level of compensation from DAL for every flight, hence the high revenue.
That's one of the reasons CMR's schedule is being reduced, it makes no economic sense for DAL to continue to contract out the same number of high CASM and high fuel burning RJ seats as it did when fuel was under $30/barrel.