Aerospace is a broad industry that can include the design and manufacturing of civilian and military aircraft, space vehicles, and missiles. Aerospace instrument manufacturing and space research and technology provide large portions of the industrial employment across the industry. Logistics and control systems software is made to manage mechanical and other hardware components involved with flight, air traffic control, and communications. Additionally, aircraft suppliers provide parts and machinery for aircraft assembly and maintenance. These parts include engines, interior components, avionics, and aircraft hardware such as landing gear. Suppliers are important for both the assembly and maintenance of aircraft. The industry's customers include the military, commercial airlines, and general aviation.