Originally Posted by
RealHJ
Is that always the case? I remember being surprised (this was years ago) when I got some HY flights issued on a 012 (NW) ticket stock. That was back in the days when paper tickets still existed - the last printed paper ticket I had. I think that then for US origin (it was JFK-RIX/RIX-JFK, flights HY1 and HY2) may be HY had NW be its US ticketing carrier.
It depends what is meant by "standard protocol". For a TA, the reservation system will suggest a plating carrier. Usually that would be the carrier who created the first fare on the ticket, provided that carrier has interline agreements with all the other carriers, and provided there are no restrictions on that carrier issuing the ticket that might arise from other fare rules.
You don't have to use the plating carrier suggested. However if you overrule the choice it can get complicated.
If you book directly with an airline your ticket will be on their stock. I have ticketed many all-AA itineraries on 125 BA stock for no other reason than I have BA reservations on speed dial.
However only AA can issue instant upgrade fares (on 001 AA stock). So if I have a circle trip that includes instant upgrade fares, it's back to AA, even if every other flight is BA-numbered.
Another example, I used to plate almost all of my intra-EU sky team tickets on DL 006 stock. That's because AF/KL charged a credit card fee when buying through their websites but DL did not.