From Dubrovnik to San Francisco.

"Can I book my baggage all the way through, even though I am using two different airlines?"

If it is all on one ticket, and if the airlines are allied, then yes. If the airlines are not allied, and/or if you are one separate tickets, then usually not these days.

I see that Croatia Air is in the Star Alliance, meaning it is part of the same group as Lufthansa. However, KLM is not Star Alliance, but Skyteam. (The third major airline group is OneWorld).

So, with the Croatia Air to Lufthansa transfer, you should be able to check luggage all the way from Dubrovnik to SFO. With the Croatia Air to KLM transfer, you can definitely check it through from Dubrovnik to AMS; you'd have to check with the airlines involved if you can check it through to SFO or not.

From my experience as an passenger service agent with an international airline based at O'hare, if customer in your situation two separate airline bookings requested that at checkin we would process the bag tag so that it would go all the way through to your final destination. You would just have to present that other itinerary. So I would check with the airline as they all have different service and rules. And who knows nowadays they might charge a fee.

Hi Hank. In my mind, the much bigger issue than checking luggage is that if you don't buy your whole journey on one ticket, you are adding a lot of risk. If your first flight is late for any reason, you could miss your second flight, and at that point be faced with buying a new transatlantic ticket at the day-of / walk up price. Ouch!! Be sure you are OK with this risk if you take this approach. Enjoy your trip!

I looked on expedia and plugged in a random Sept date and found a Norwegian Air flight that goes through Barcelona

both flights are on Norwegian Air with 2hr 50 minutes between flts. --$340 one way

its a single booking