Spirit AeroSystems designs and manufactures aerostructures for commercial aircraft and military aircraft. The company had $7 billion in sales in 2017. Spirit divides its business across three units: fuselage systems (roughly 53% of 2017 revenue); propulsion systems (24%); and wing systems (23%). The company remains the largest independent supplier of aerostructures worldwide, and its primary customer continues to be Boeing (about 80% of revenue), mainly as a result of Spirit being spun out of Boeing in 2005.
