How/where to book codeshares on AY metal?
 

OK, here's the problem. Collegue flies a lot in EU and to China on AY. I told him the joys of AAdvantage, so he joined and by now he would be AAPlat if he had 4 leg on AA coded flights, which in his case would be on aforementioned AY flights - how can he book one?

These codeshares DO exist, as I can see them on the boards at the airport - I tried a few OTAs with no luck.

Some of the AY codeshares are sold only in connection on international flights, i.a. domestic AY-codeshared flights in Germany or ex-Germany (except to Scandinavia).

While I don't have the answer you're looking for, I'd tell him to do an MR to the US east coast same day return at around 400€.

I have sometimes seen the AA (or JL) codeshares on AY metal being sold without intercontinental connections, but the prices are completely insane (approximately tenfold increase).

You are not supposed to buy those separately.