Europe’s Airbus has finalized an agreement to take some assets from Spirit AeroSystems, both companies said Monday, completing a critical part of a transatlantic carve-up of the struggling supplier with US rival Boeing.

European plane maker Airbus will take over parts of Spirit AeroSystems as it and Boeing carve up the key supplier in an effort to improve production quality.

Airbus agreed to acquire some Spirit AeroSystems facilities that make parts for its jets, moving to take direct control of production in a bid to stabilize supply chains after months of disruption.The companies said Monday that they had entered into a definitive deal for Airbus to take over several of Spirit’s plants in the U.