ISBN: | 978-5-5149-9557-8 |
High Quality Content by WIKIPEDIA articles! The Lockheed C-121 Constellation was a military transport version of the Lockheed Constellation. A total of 332 aircraft were constructed for both the United States Air Force and United States Navy for various purposes. Numerous AWACS versions were also constructed. The C-121 later saw service with smaller civilian operators until 1993.