Was reading this snippet - http://online.wsj.com/article/BT-CO-...03-715805.html - and was wondering...

When they calculate a passenger revenue mile, do passengers who use frequent flyer miles count? I thought that those miles actually have some sort of value for the purposes of airline finances, as they are a liability if everyone were to go cash them in at once/etc.

Does anyone who has a finance background (or more of a clue then I anyway) know how a passenger revenue mile is calculated? I Googled for the answer to this but the answers I got weren't very specific in terms of award seats...

Also, dare I ask, do upgraded/other classes of seats get factored in here differently?