Spirit AeroSystems Holdings, Inc., is an American aerostructure manufacturer. The company, based in Wichita, Kansas, builds several important pieces of Boeing aircraft, including the fuselage of the 737 and 787, as well as the flight deck section of the fuselage of nearly all Boeing airliners. Spirit also produces parts for Airbus, including fuselage sections and front wing spars for the A350 and the wings for the A220. Spirit's main competition comes from Collins Aerospace, Kawasaki Heavy Industries, Leonardo, and Triumph Group.

An aerostructure is a component of an aircraft's airframe. This may include all or part of the fuselage, wings, or flight control surfaces. Companies that specialize in constructing these components are referred to as "aerostructures manufacturers", though many larger aerospace firms with a more diversified product portfolio also build aerostructures.