GE Aerospace is an American aircraft company, which engages in the provision of jet and turboprop engines, as well as integrated systems for commercial, military, business, and general aviation aircraft. The firm has an installed base of approximately 45,000 commercial and 25,000 military aircraft engines. The firm operates through two segments: Commercial Engines & Services and Defense & Propulsion Technologies. The Commercial Engines & Services segment designs, develops, manufactures and services jet engines for commercial airframes, as well as business aviation and aeroderivative applications. Its services include maintenance, repair and overhaul (MRO) of engines and the sale of spare parts and offers services under a variety of arrangements. The Defense & Propulsion Technologies segment provides defense engines and critical aircraft systems and consists of its Defense & Systems and Propulsion & Additive Technologies businesses. Its portfolio of brands includes Avio Aero, Unison, Dowty Propellers and Colibrium Additive.