From the Delta investor webcast

Today in the investors webcast they talked alot about up gauging aircraft in specific markets and that the DC9s were now a very helpful tool in the puzzle. "yesterdays trash is todays treasure" was the exact quote. Context of the discussion was in regards to higher fuel and now low fuel. fwiw

I think we will see alot of md80s and dc9s put on old rj routes. This will allow them to move the same amount of seats with less frequency.

so i think ATP is wrong