I went on the factory tour at the Airbus factory in Hamburg Germany. It's quite well done, very long (2+ hours), and does a good job of explaining why they're flying giant airplane parts from around Europe for assembly, and what goes on inside all those huge buildings. Among other things, you get to go inside the building where they used to assemble the A380, and now there's 4 smaller planes being worked on in the same space that used to fit one A380.