It may be shortsighted to consider only yield in a city pair. When a regular United customer wants to go to MCO it might be more dollars in the long term to have that flight available, even if it isn't busting in profitability, because it keeps that customer--and many others--in the United network so that next year, when they decide to go to international, they stay with United. MCO may be unique in this consideration because it seems a great number of people have that on their list of must go places. DSM? Maybe not so much.