ORD is the three letter identifier for Chicago's O'Hare International Airport. The identifier derives from the name Orchard Place Airport / Douglas Field, the "D" coming from "Douglas", not from the trailing letter of "Orchard", as I had supposed. The original airfield was constructed between 1942 and 1943 as a manufacturing plant for Douglas C-54 aircraft for World War II. Douglas Aircraft manufactured 515 C-54s in Santa Monica, and 655 were manufactured in Chicago.
As a former employee of McDonnell Douglas Astronautics Company -- a component of McDonnell Douglas Corporation, and hence heir to part of the Douglas Aircraft Company legacy -- I was aware of Santa Monica as one of the early manufacturing site, but I had no idea C-54s were produced at Chicago as well.
For more about airport identification codes, see: Airport ABCs: An Explanation of Airport Identifier Codes.
