> but planes are regularly stretched[1][2] One of the main design requirements for those plane models was, right from the start, to support multiple variants b

> but planes are regularly stretched[1][2] One of the main design requirements for those plane models was, right from the start, to support multiple variants by adopting a modular design. Yet, they are still very tightly coupled. In fact, IIRC the Airbus A340 project is widely known for having experienced a billion-euro delay due to production problems caused by CAD software issues. In short, if my memory doesn't fail me, some design teams used Catia V4 while others migrated to Catia V5, whose CAD engine was rewritten from scratch. Consequently, some slight differences in how the different versions handled geometry definitions resulted in some electric cables designed by some engineering teams to be incompatible with the structural layout designed by other engineering teams. We're talking about differences in centimeters in a plane with a wingspan with around 56m.