I also think, but cannot prove, that straight dollar competition at hubs is not between the major carriers but between others. For example, I can find cheaper fares to some locations on Frontier than Delta, but I choose Delta because of the fact that I do believe that it is safer on Delta and they will take care of me in case of problems more easily. Now Southwest is a completely different matter. If I can find a cheaper flight on SW I will have my daughter take it.