The fixed-position layout is not good for high volume, but it is often necessary for large, bulky products, special events, and custom orders like the one-of-a-kind launch of the Harry Potter and the Prisoner of Azkaban DVD. Many manufacturers are adapting the fixed-position layout to speed up production. Boeing now builds many of its planes on a type of moving assembly line, which cut in half the time it takes to assemble a single-aisle 737. Airbus uses assembly stations, moving the plane only from one major workstation to the next, with the idea that a glitch in one plane won't slow a whole production line.