I've tried to find a thread that answers my question but without success. I have a flight home from Santiago, on American Airlines operated by Iberia. The ticket takes me from Santiago to Madrid, where I transfer from terminal 4 to 4S, not changing airlines. I plan to check my backpack going home. I'm wondering if I'll go through security in Santiago and then in Madrid can go straight to my connecting fight, without worrying about my backpack or an additional security line. I don't have a lot of connecting time, and I'm getting very anxious about it. Because I have one ticket taking me through to the US, I'm hoping that once I've checked my baggage in Santiago, I can forget about it until I reach Chicago. Is that the case?