Chicago O'Hare International Airport
Facts on ORD
O'Hare's code ORD is a fossil from its earliest name: the site was once called Orchard Field (later Orchard/Douglas Airport) for its aircraft-manufacturing role in WWII, and even though the airport was renamed in 1949, the IATA code ORD -- from ORcharD -- was never changed, making it one of the few airport codes with no connection to the current airport name.
Source: Wikipedia
In 1949 Chicago renamed Orchard Field to O'Hare Airport to honor Lieutenant Commander Edward "Butch" O'Hare, the U.S. Navy's first flying ace and a Medal of Honor recipient in World War II.
Source: Wikipedia
O'Hare held the title of the world's busiest airport by passenger traffic for 35 years straight, from 1963 to 1998, before Atlanta's Hartsfield-Jackson overtook it.
Source: Wikipedia