So I am curious about the case for narrowbody cargo hold containerization. For example, I know that Air France (and I am pretty sure British Airways as well, in addition to other carriers) loads small cargo containers with passenger baggage into the holds of their Airbus narrowbody fleets (A319/A320/A321). These containers look like shrunken-down versions of LD-2/LD-3 containers, but I don't know what their identifier is. However, in the U.S., none of our carriers use any form of containerization on narrowbodies, all bags and cargo are bulk loaded. So I am curious as to why several European carriers chose this option and why none of the U.S. carriers did. Specifically, what is the business/operational case in favor of or against containerization? Why is it more or less efficient than bulk-loading? Is there something specific of the under-wing operations in Europe vs. the U.S. that justifies this? Also, what additional equipment or overhead comes along with choosing containers vs. bulk? Just another little operational thing that I've been curious about for a while.