Spirit AeroSystems, Inc. ("Spirit" NYSE: SPR), base in Wichita, Kansas, is the world's largest first-tier aerostructures manufacturer. The company builds several important pieces of Boeing aircraft, including the fuselage of the 737, portions of the 787 fuselage, and the cockpit (referred to as "Section 41" by Boeing) of nearly all of its airliners. Spirit's main competition comes from Vought Aircraft Industries, Goodrich, Alenia, and Kawasaki Heavy Industries.