Originally Posted by
vineyarder
Can BA codeshares only be sold as part of an international itinerary?
Yes, that is correct. Those flights are restricted to "Q/ INTL ONLINE CONNECTING OR STOPOVR TRAFFIC ONLY".
Thanks to the costs of protectionism, BA does not have any rights to sell itineraries that are wholly within the USA (and vice versa with USA airlines selling tickets in the EU).