psoque

Hi. I apologize if this topic has been discussed to death previously. I am still rather confused about how different airlines manage code share flights.

I recently reserved (through a cruise line) a pair of round trip tickets from IND to LHR (with stops in ORD going and CLT coming back). They are economy class (fare class S) from American. All four segments are operated by American, and the ticket appears to be issued by American. However, the two transatlatic segments are Iberia flights operated by American. I'm not sure why American would wan to sell their flights in this convoluted fashion.

Anyways, my question is in regard to my ability (or lack there of) to upgrade the transatlantic segments with miles. Do I:

A. Contact American Airlines and upgrade the segments with AAdvantage miles?
or
B. Contact Iberia and upgrade the segments with Avios?

Or something more convoluted?

Thanks.

Naoyuki