The second in a series on the history of the famous Chicago hub, author Ian Petchmo goes behind the scenes to discover an airport rushed into the jet age and in a state of constant expansion. Can it take it? Miss part one? Read it here!

If the 1940s and 50s were spent bringing passengers and airlines to O’Hare, the remainder of the twentieth century was spent making sure there was a place to put them. Almost immediately after the airport officially opened passenger traffic skyrocketed. The airlines’ transition to jet aircraft sped the shift of flights from Midway to O’Hare in the early 1960s. As Midway’s short runways could not safely handle the larger jets, O’Hare overtook Midway’s lead in traffic in 1961, and by 1967 Midway saw only 4,500 scheduled airline movements, 300,000 fewer than only a decade before.

At O’Hare, traffic was moving briskly—perhaps a bit too briskly. The airport’s 1962 Master Plan foresaw 533,000 movements by 1980, yet the field reached that level in 1966.

The first update to the original terminal complex came in 1963, when the original domestic terminal built in 1955 was renovated to become a new International Terminal. There were 490 people on direct flights between Europe and Chicago in 1953. Just ten years later, over 250,000 passengers used O’Hare to visit an expanded international network including Europe and Mexico. The addition of the dedicated International Terminal allowed Chicago to truly claim the name Chicago-O’Hare International Airport.

By the late 1960s Chicago was already looking for additional capacity. An additional airport in the Chicago area was being considered, but even if approved it was years away. To alleviate congestion, O’Hare added a new east-west runway, 9R-27L, on the south side of the terminal complex in 1967. In 1971, work was completed on 4R-22L on the southeastern portion of the airfield. This gave O’Hare three sets of parallel runways, one pair in each direction oriented east-west, northwest-southeast, and northeast-southwest.

The Airline Deregulation Act of 1978 had a profound impact on operations at O’Hare. Domestic deregulation led to United Airlines and American Airlines consolidating operations at the airport to form their hubs. O’Hare’s terminals were reconfigured to better serve the operations of the hubbing airlines as other airlines, such as TWA and Northwest Airlines, moved their hub operations elsewhere. As United and American’s presence at O’Hare became more pronounced, plans were made for a new terminal complex.

In 1982, Chicago launched the O’Hare Development Program, a new master plan designed to provide the airport with new or rehabilitated terminals and service areas by 1990. The plan called for a new International Terminal on the southeast side of the airfield, a commuter terminal and general aviation terminal  located near the new International Terminal, construction of a new Terminal 1—replacing the existing International Terminal—to be used by United, expansion of Terminals 2 and 3, a new air cargo complex on the southwest side of the airfield, a new airport services area with flight kitchens and maintenance facilities, relocation of the existing inner- and outer-taxiway system around the terminal complex, and a people mover to bring passengers between terminals and the remote parking areas.

In 1984, construction began on United’s famous Helmut Jahn-designed “Terminal for Tomorrow.” Yet at the time construction of a new International Terminal was still almost a decade away, so what to do with all of O’Hare’s international traffic? To make way for construction of the new Terminal 1, O’Hare constructed a makeshift terminal on the ground floor of the main parking garage, creating Terminal 4. Passengers were then bussed directly to their flights from the garage/terminal.

That same year, Chicago completed its long-planned extension of the CTA Blue Line train to O’Hare from downtown. A direct rail connection to the airport had been planned since the early 1950s but had never been completed. Before the completion of the rail link, passengers who wanted to reach O’Hare via public transportation had to take an express bus from the Jefferson Park station. The train runs in the median space of the Kennedy Expressway and I-190 near the airport before heading into a short subway stretch. It terminates underneath the main parking garage.

Construction of the new Terminal 1 lasted until 1987, when the first dozen of more than 40 new gates opened. Jahn described his design as drawing inspiration from the exhibition halls and railway stations of the turn of the twentieth century, with open floor space and lots of natural light. Concourse B was built next to the roadway, similar to the location of the other terminals, but Concourse C was constructed in the middle of the airfield, connected to Concourse B by an 850 foot tunnel.

The tunnel, also designed by Jahn, has become one of O’Hare’s defining features. Jahn worked with artist Michael Hayden and composer William Kraft to design the complex light sculpture called “Sky’s the Limit,” which covers the ceiling of the tunnel and undulates to music. Construction of the new terminal wasn’t without its problems, however. The placement of the glass walls and ceilings had the nasty effect of blinding controllers in the O’Hare tower. The problem was solved temporarily by rubbing wax over the windows. Eventually, an acid coating was applied to the windows for a permanent solution.

Throughout the 1980s, extensive renovations were also completed in Terminals 2 and 3. As part of the construction of the new Terminal 1, Terminal 2’s Concourse D was demolished to make room for Concourse B. In 1984, Concourse L in Terminal 3 opened as home of the brand new “Delta Flight Center,” which housed O’Hare’s first computerized curbside baggage check-in. In 1987, American Airlines began renovations of its facilities, modernizing the terminal building constructed in the late 1950s.

The last piece of the O’Hare Development Program broke ground in 1990, when O’Hare began construction on the new International Terminal on the east side of the airport. Completed in 1993, Terminal 5 handles all international arrival traffic from 21 gates. The airport’s new Airport Transit System opened in mid-1993 as well, serving the main terminal complex, T5, and the remote parking areas.

Before construction even started on the final phase of the O’Hare Development Program, some were already calling for the expansion of the airport to meet future demand. Delays at O’Hare were mounting and other major airports, such as Dallas and Atlanta, were planning major expansion projects. Chicago’s Mayor Richard M. Daley, son of the former mayor, supported a third airport near Lake Calumet on the city’s south side, but the plan was soon scrapped after resistance from the Illinois legislature. Further disagreement between the Republican-controlled state government and Democratic-controlled Chicago over who would control O’Hare, Midway, and any future airports in the region would lead to nearly a decade of political maneuvering at the state and federal level. As the twentieth century came to a close, O’Hare was at a crossroads: would it modernize and expand, or would it fall victim to delays and political infighting?