MTU Aero Engines specializes in the development and production of commercial and military aircraft engine components and spare parts. It also performs maintenance, repair, and overhaul services for aircraft engines. More than 30% of commercial aircraft have MTU technology on board. MTU is also a major assembler of aircraft engines. The commercial and military engine segment develops and manufactures engine components for new engine production and spare parts for the aftermarket. The commercial maintenance business reports MTU's MRO services.