I've heard of code shares where one airline truly buys seats from the other -- such that only the one and not the other can sell them. That's the Virgin/Continental deal, as I understand it. But my understanding was that most codeshares aren't this way, rather they sell out of shared inventory, and I thought (from EXP desk comments, or messages here?) that's how AA's codeshares with JAL, QF, etc. all worked. I assumed -- perhaps mistakenly -- that AA's relationship with CX would be similar. Very interesting.