ok im in houston and i want to go to tanger morocco. so how does the checking in luggage thing work? if i purchase a ticket that will say houston to tanger but stops at chicago then goes to madrid then tanger. do i have to get my bags after each stop and check in like i did in houston or do i have to check in once and then the airport will automatically take my luggage to each stop/airport or whatever. please help im confused and unsure!