Boeing is the world's largest aerospace and defense firm. With headquarters in Chicago, the firm operates in four segments, commercial airplanes, defense, space & security, global services, and Boeing capital. Boeing's commercial airplanes segment produces about 60% of sales and two-thirds of operating profit, and it competes with Airbus in the production of aircraft ranging from 130 seats upwards. Boeing's defense, space & security segment competes with Lockheed, Northrop, and several other firms to create military aircraft and weaponry. The defense segment produces about 25% of sales and 13% of operating profit, respectively. Boeing's global services segment provides aftermarket servicing to commercial and military aircraft and produces about 15% of sales and 21% of operating profit.Boeing Co designs, develops, manufactures, sells, services and supports commercial jetliners, military aircraft, satellites, missile defense, human space flight and launch systems and services.