Originally Posted by
aaupgrade
FWIW, due to being an itinerary originating in the USA, the USA exeption comes into play. The baggage rule of the MSC for the Marketing carrier of the initial journey apply to the whole trip/booking.
In wich case, AY's rules are it.
Note that if ORD-HEL has been on an AA flight number, the AA's rules would have applied, even ex BRU.