We had a cruise with included air, but only from a major airport, so we separately booked a flight from our regional airport to Calgary. The short flight was with Air Canada and the long haul was with Lufthansa (which are, of course, partner airlines). We didn't even ask, but the check in agent asked us if Calgary was our final destination. When we said Budapest with Lufthansa, she was able to link the flights and we didn't have to collect and recheck in Calgary ... we picked up our luggage in Budapest.