Originally Posted by
irishguy28
As a general rule, you will always check in with the operating airline of the first/next sector in your day's flying.
You do not check in with Air France just because you bought a ticket from them and/or there is an AF flightcode on the first flight of the day on your ticket.
VN seems to be an exception to this rule, because VN advised me to OLCI on AF website 30 hours before scheduled departure.
It may be that once identified on AF website, we are redirected to VN... I don't know.
I kind of remember doing OLCI on AF website for UX code share flights CDG/AGP. But this was years ago...