Jetblue CASM is lower than Southwest or Airtran due to their larger average airframe and longer stage length. If you notice, it also affects their RASM/yields as well. If you adjust their cost to similar stage lengths and aircraft size, they are in the same ballpark as all the other LCCs.
Now I'll be the first to admit a financial wizard I am not. And because of that, I have to ask, how does a company (UAL) LOSE $25.76 per passenger and continue to operate? Just living on borrowed funds? Would it not have been less expensive to just mail a check to every passenger that was going to ride on that airline a check for $15, ask them not to fly and keep the planes on the ground? Not trying to ruffle feathers, just curious from a financial standpoint how this is possible.