I can tell you a little bit about the history...
1940s: Orchard Field opens as an auxiliary military airfield for WWII aircraft.
1949: With Midway Airport approaching capacity, the city acquires Orchard Field and begins redeveloping it. The original three runways (present day 14L-32R, 9L
-27R and 4L-22R) are widened and extended.
1955: The first phase of the new ORD
opens - a small terminal with a ground-level Y concourse (this was the original Terminal 1, and was demolished in the early 1980s.) A new 10,500-foot runway -- the present-day 14R-32L -- is also opened. All charter and cargo flights move to ORD
1959: Jet flights (by United, American, Continental, TWA, Northwest, Delta, Braniff and Eastern) are handled by ORD
, while prop operations remain at Midway. For the next three years, operations will be split between the two. The Kennedy Expressway opens to downtown Chicago. Construction begins on Terminals 2 and 3.
1961: American becomes the first airline to move ALL
its flights to O'Hare from Midway.
1962: Terminals 2 and 3 are opened by President Kennedy. All scheduled flights move to O'Hare from Midway.
1968: O'Hare is already nearing capacity. A new 10,000-foot runway (9R-22L) is completed on the south side of the airport. Midway Airport is redeveloped and reopened for limited passenger operations.
1971: The final runway in the ORD
master plan (4R-22L) opens on the south side of the airport. The main parking garage, control tower and O'Hare Hilton are opened.
1983: A multimillion-dollar construction program begins. The interim international Terminal 4 is opened on the ground floor of the parking garage (passengers take buses to aircraft parked at remote stands.) The original Terminal 1 closes for redevelopment.
1984: Terminal 3 is extended to the east and the new Concourse L for Delta is opened.
1987: The new Terminal 1 opens for United Airlines. American completely remodels Terminal 3 and adds rotundas to the end of Concourses H and K.
1989: The air cargo facilities are moved to the west side of the airport so that work can begin on a permanent international terminal.
1993: International Terminal 5 and the Airport Transit System (ATS) are opened.
2000: American rebuilds Concourse G (the old TWA concourse) for American Eagle regional jet flights.
2003: Work starts on the FACE project that will expand the landside areas of T1, T2
2007-2010: Terminals 4 and 6 are scheduled to open, along with the new runway layout. Not sure if this is going to happen, as no construction has started yet.