I feel the main difference is that Boeing's management post McDonnell merge decided to consider their suppliers as simple vendors, spinning off Spirit, and taki

I feel the main difference is that Boeing's management post McDonnell merge decided to consider their suppliers as simple vendors, spinning off Spirit, and taking away their direct oversight using supply contracts as a backstop. Airbus does more hands-on oversight of their suppliers, they have staff to check their work, is all part of an integrated QA system instead of the hands-off outsourcing approach Boeing took. At least that's what I understand from a very layman view of their processes, would love to be corrected if I'm wrong.