Boeing is an aerospace company that develops, manufactures, and services commercial airplanes, defense products, and space systems. It operates through three segments: Commercial Airplanes, Defense, Space, and Security, and Global Services. The Commercial Airplanes segment develops, produces, and markets commercial jet aircraft to the commercial airline industry. The Defense, Space, and Security segment is engaged 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, and other solutions.