Surgee

ricktoronto

Interline agreements are between airlines with some airlines and not others and you did not bother to say what the other airline is. The trend though, has been for more airlines not to check through on separate tickets, in some cases even on the same airline. Usually in the latter case some price deal making two tickets better than one so the airlines fight back by doing this.

kq747

OP clearly states both flights are on KQ

I've had KQ interline tickets on separate airlines and I've never heard of them refusing to through check on their own flights. However, as with most airlines, depends on the mood/competency of the check in agent. If the agent does not through check then you could head to the transfer desk after departing and hope your bags make the transfer (never tried at NBO). If you fly KQ metal and not PW then you will arrive and depart from Terminal 1A so going through immigration and rechecking if you absolutely have to might not be the worst unless your flight from ZNZ is delayed and you miss the bag drop cut off. Assuming you take the evening flight into NBO gives you just over 2 hours but this is when quite a few intl departures are happening in the check in hall.

ricktoronto

AA won't do it on separate tickets on their own paired flights. I think currently fewer will than won't. They have no desire to allow passengers to find cheaper flights between A and C by buying separate tickets A-B and B-C if they did not already price that option to death to kill off that opportunity. At least AA will protect passengers on misconnects despite refusing luggage straight through.

Surgee