Systems and methods are provided for enforcing contours onto parts of an aircraft. One embodiment is a method for enforcing a contour onto aircraft parts. The method includes removably attaching segmented ring details to aircraft skin details, attaching stringers to skin details to create skin assemblies, positioning skin assemblies at a support structure defining a contour, and fastening frames to the skin assemblies to create a panel. The method also includes removably installing a spreader section onto the panel to complete assembly of a brace prior to removal of the panel, transporting the panel while the brace enforces the contour, attaching the brace to braces for other panels to form a barrel section of a fuselage for an aircraft while the brace enforces the contour, and removing the brace from the barrel section after the barrel section has been formed.