I'd like to share something I learned today. For seat selection, i had to go to a different airline's website.
I found a great fare NY-Paris round trip via Finnair. During the booking process I didn't see a way to select my seats, so after completing my booking I did a live chat. I was told if the flight operator is a different airline, you have to select your seat through that airline.
Sure enough, although I paid Finnair and have their booking reference, there's also a booking reference for American Airlines, which is the flight operator. (If I had bought my tickets from American, they would have cost more.)
I went to the American Airlines website and used my American Airlines booking reference. I was able to select my seats. There was a choice between no-extra-charge selections and other seats that would cost extra.
Just wanted to pass this along in case others don't know about this.
I'm glad you were able to select your seats!
I've had this come up when booking on Delta and then having a European onward flight on either Air France or KLM. I've had mixed results on picking a seat...sometimes I can, but there are times when I have not been able to for whatever computer interface reason.
Apparently you have just experienced the joys of code sharing. Becoming more and more common as airline alliances grow.
Yes, code sharing. One good thing, besides getting to select my seat, was the opportunity to enter my American Airlines frequent flyer number. I had skipped that step when I purchased on Finnair because I wasn't sure if Finnair would partner with American for the FF program, and I didn't want to mess up the transaction.