Boeing is an aerospace company that manufactures commercial jetliners, defense, space, and security systems and provides aftermarket support services. It operates through four segments: Commercial Airplanes; Defense, Space & Security; Global Services; and Boeing Capital. The Commercial Airplanes segment develops, produces, and markets commercial jet aircraft and provides fleet support services to the commercial airline industry. The Defense, Space & Security segment engages in the research, development, production, and modification of manned and unmanned military aircraft and weapons systems for strike, surveillance, and mobility, including fighter and trainer aircraft; vertical lift, including rotorcraft and tilt-rotor aircraft; and commercial derivative aircraft, including anti-submarine and tanker aircraft. The Global Services segment delivers supply chain and logistics management, engineering, maintenance and modifications, upgrades and conversions, spare parts, pilot and maintenance training systems and services, technical and maintenance documents, and data analytics and digital services. The Boeing Capital segment provides financing solutions.