Originally Posted by
efincomputer
Main difference with the BA codeshares is it sometimes makes a difference in terms of the Avios you'll earn (BA will always earn more - if there's any difference between the two flights).......
It used to be the case that AA coded flights earned less Avios than the same flight on the BA code because the cabin bonus was different (eg 25% on AA versus 50% on BA for the lower Business Class fares)
From 1 January this year, the cabin bonus on AA and BA was standardised so you now get the same number of Avios regardless of whether you're booking on the AA or BA code. The earning chart for AA flights on ba.com shows the two tables, one for earnings up to 31 December and the higher earnings table from 1 January.
Collecting Avios and Tier Points on flights | Executive Club | British Airways