History of Chicago O'Hare Airport
O'Hare was not always known as O'Hare Airport. It actually started out as Orchard Place Airport/Douglas Field, which is where its ORD airport code came from. Orchard Place was a small town that had been there for a while, but during World War II (1942-1943), Douglas erected a two million square-foot factory on the site to make Douglas C-54 aircraft, but by 1945, the contract between Douglas Aircraft Company and the Department of Defense had expired. Douglas decided to leave the site, and when it did the name of the airport became Orchard Field Airport. That same year, the City of Chicago decided it wanted an airport to handle the air traffic that Midway Airport was increasingly inadequate to process, especially with the advent of jet travel. In 1949, the airport's name was changed to O'Hare to honor Lieutenant Commander Edward "Butch" O'Hare, a World War II Air Force pilot and Medal of Honor recipient.
Around that time, the City of Chicago annexed the site of O'Hare via an annexation corridor only 200 feet wide. In 1955, the first passenger flights began. In 1958, an international terminal opened. In 1962 O'Hare expanded, and immediately started serving 10 million passengers annually, making it the busiest airport in the entire world. It retained this distinction until 2005, when its traffic was surpassed by Atlanta's Hartsfield-Jackson Atlanta International Airport.
Chicago O'Hare Airport is United Airline's flagship hub. United Airlines accounts for nearly half of all O'Hare passenger traffic.