I just found that AA is running a terrific winter fare sale to almost all European destinations from almost all US cities for travel valid from now to (around) 3/31/2018. Including the codeshare BA flights. Looks like typical RT Economy fare is between $400 and $499.

For example, typical SAN - LHR or CDG or AMS or ZRH fare is around $1,500 (BA 272, codeshared with AA, is the only direct flight to Europe from SAN). I just booked:

1/25/2018 - 1/30/2018: SAN - CDG: around $450
2/22/2018 - 2/27/2018: SAN - AMS: around $415
3/15/2018 - 3/21/2018: SAN - ZRH: around $475 ($415 if travel early morning via JFK on AA metal)

All these flights have several BA legs.

Looks like amazing fare out of SAN. Tickets are priced at $1 or $2. rest are fees and taxes.

"Pizza in Motion" reported the sale in early evening. I read his blog post in the "milefeeds" app (BTW: I think "milefeeds" is one of the best (free) travel news app in iOS -- FlyerTalk should be included but ...). Link:

FARE SALE! American Airlines Appears To Be Having A European Fare Sale To Pretty Much Everywhere. From, Pretty Much Everywhere.

Don't know how long the sale will last.

Tintin