Originally Posted by AHO
If both of two your bookings are SK operated flights, then it will(has been) probably be no problem.
But after the change of 1st Sep, I'm not sure how it is today, though.
It worked on my TRD-OSL (SK), OSL-FRA-NCE (LH) journey on Monday. Both reservations and tickets were separate, and on two separate airlines. Noone seemed to care the least about that. Luggage checked through and boarding passes all the way to NCE printed in TRD.
Note; the automated check-in didn't manage to sort this out, so I needed a check-in agent to fix it.