Europe’s move towards lighter, multi-material military structures changes the meaning of industrial capacity. A composite panel, metallic frame or thermoplastic component can all be manufactured in Europe while the ability to turn them into an accepted structure remains dependent on a narrower set of joining processes, fixtures, software, surface treatments, inspection methods, qualification evidence and repair data. The interface between materials is therefore not a minor manufacturing detail. It can determine whether a structure can be produced repeatedly, whether a second factory can reproduce it, whether damage can be assessed without destructive testing, whether a repair can be released back into service and, ultimately, whether an operator retains freedom of action when the original production chain is disrupted.