ORD 21 kicked off in 2019 with a runway project that was completed in 2020.

By summer of 2022 seven new gates opened as part of an addition to the East Concourse. In October 2022 10 more gates opened in the West Concourse. 

In November 2022, the Federal Aviation Administration approved the multi-billion dollar construction of a new passenger terminal at Chicago O'Hare International Airport—a key component of ORD21.

That announcement came via U.S. Transportation Secretary Pete Buttigieg and then Chicago Mayor Lori Lightfoot. 

The expansion, known as the Terminal Area Plan, is focused on the western side of the airport. 

Construction was slated to begin in spring 2023, with the new terminal expected to enhance the airport’s global connectivity and infrastructure.

Initial phases includes two new satellite concourses, set to open in 2027 and 2028, significantly increasing O'Hare's capacity to accommodate larger aircraft and handle more passengers.

The near-term gate improvement projects, including the Terminal 5 Expansion Project, were completed in 2023. This major overhaul, which increased capacity by 25%, added 10 new gates, expanded passenger amenities and reconfigured customs and security checkpoints to improve efficiency and reduce delays. 

The project also included a complete replacement of the baggage handling system, which doubled the terminal's baggage screening capacity and added flexibility for future demand. Additionally, new concessions were introduced. 

By July 2023, construction on the major O'Hare 21 project was well underway, marking a significant step in Chicago O'Hare International Airport's multi-phase infrastructure overhaul. 

“O'Hare 21 really is a generational capital investment in O'Hare's facilities that will take approximately 15 years to put in place,” City of Chicago Department of Aviation Chief Development Officer Robert Hoxie said at the time, according to Aviation Pros. “The purpose of the program is to transform O'Hare and give it terminal facilities primarily that are fit for purpose for the 21st century.”

In April 2024 construction officially begun on a $300 million project to modernize Terminal 3 at O'Hare International Airport, with the upgrade slated for completion in 2027. The project, partially funded by $90 million in federal grants, was aimed at enhancing the terminal’s infrastructure and passenger amenities. 

In Mat 2024 architectural renderings for the new Satellite Concourse 1 were unveiled, produced by renowned Chicago-based architects, Skidmore, Owings & Merrill, Ross Barney Architects, Juan Gabriel Moreno Architects, and engineering firm Arup. That concourse, which will serve as a major expansion to O'Hare’s existing terminal facilities, is expected to be finished in 2028. 

In 2026 construction on the O’Hare Global Terminal is expected to begin. 

The $2.2 billion O'Hare Global Terminal is set to be one of the largest and most advanced airport facilities in the U.S. 

The new terminal will more than double the space of the existing Terminal 2. The terminal is expected to be constructed without reducing gate capacity, with two new satellite concourses.