Boeing says it has closed the deal for its $4.7 billion takeover of supplier Spirit AeroSystems, bringing the embattled wing and fuselage manufacturer back in-house nearly two decades after it was spun off.

CNBC reports that the acquisition will include all of Spirit's Boeing-related operations, as well as parts of the supplier's operations in Northern Ireland. In the lead-up to the deal — which was announced over the summer and finalized on December 8 — executives said that bringing Spirit back under Boeing’s umbrella would streamline oversight, cut down on costs, and give the planemaker greater control over what's proven to be a vulnerable link in its supply chain.

Spirit Aerosystems was spun off from Boeing in 2005, and is responsible for building most of the 737 Max line. Following the blowout of a door plug aboard a 737 Max 9 in early 2024, a former Spirit quality manager alleged that the supplier had knowingly delivered defective 737 Max fuselages to Boeing for years, claiming that it was "very rare for us to look at a job and not find defects." The accusations added urgency to Boeing’s push to reabsorb Spirit, bolstering the argument that tighter control over the supplier was necessary to restore quality and rebuild trust.

Both Boeing and rival Airbus have also been supporting Spirit financially for years as the supplier has struggled with mounting losses, quality issues, and the cash pressures created by repeated production slowdowns. As part of the broader breakup of Spirit's global operations, Airbus struck an acquisition deal of its own with Spirit earlier in 2025, to similarly bring the supplier's Airbus-related programs and facilities under direct control.