The Aerospace segment is committed to sustainability and the reduction of aviation’s carbon footprint. In support of this strategy, Gulfstream and Jet Aviation offer sustainable aviation fuel through our combined services network and lead the industry in total gallons supplied to the business jet market. Furthermore, we offer carbon offset credits to our customers, enabling them to operate aircraft on a carbon-neutral basis. Year Ended December 31 2020 2019 2018 Aircraft manufacturing $ 6,115  $ 7,541  $ 6,262  Aircraft services and completions 1,960  2,260  2,193  Total Aerospace $ 8,075  $ 9,801  $ 8,455  MARINE SYSTEMS Our Marine Systems segment is the leading designer and builder of nuclear-powered submarines and a leader in surface combatants and auxiliary ship design and construction for the U.S. Navy. We also provide maintenance, modernization and lifecycle support services for Navy ships and maintain the most sophisticated marine engineering expertise in the world to support future capabilities. Our ability to design, build and maintain our nation’s most technologically sophisticated warships is a critical element of the U.S. defense industrial base. In addition to Navy ships, we design and build ocean-going Jones 6 The following map demonstrates the broad reach of our combined Gulfstream and Jet Aviation services network, including authorized service centers: Revenue for the Aerospace segment was 21% of our consolidated revenue in 2020, 25% in 2019 and 23% in 2018. Revenue by major products and services was as follows: