O’Hare International Airport got the official federal go-ahead Monday for a $7.1 billion project to replace Terminal 2 with a “global terminal” intended to link domestic and international flights in one location.

U.S. Transportation Secretary Pete Buttigieg, Mayor Lori Lightfoot and other dignitaries announced that the Federal Aviation Administration had completed a four-year environmental study paving the way for the project.

“When it opens, the O’Hare Global Terminal will be one of the most transformative terminal investments in America, more than doubling the amount of space of the existing Terminal 2,” said Chicago Aviation Commissioner Jamie Rhee.

The project is expected to start with two new satellite concourses, providing about 1.3 million square feet of gate and amenity space, which will “dramatically expand the airport’s ability to accommodate aircraft of all sizes,” Lightfoot said. “This is a big deal for us.”

Said Buttigieg: “We’re excited to create the good-paying union jobs, and they’re coming with a generation of construction.”

Under the plan, the existing Terminal 2 would be demolished and replaced with the “global terminal,” which would accept both domestic and international flights. O’Hare would become the first “global alliance hub” in the nation. It will allow domestic airlines and the international carriers they partner with to be in the same terminal — and that means passengers connecting to international flights won’t have to ride the People Mover to Terminal 5, also known as the international terminal.

Demolition of Terminal 2 is expected to begin in 2026, with completion of the global terminal in 2030.

A team that includes renowned Chicago architect Jeanne Gang was chosen in 2019 to design the new terminal, the centerpiece of the massive expansion project.

“As a Chicagoan, I understand deeply the importance of O’Hare to our city’s identity, and I am honored that my hometown has provided our team the opportunity to realize a design that can demonstrate Chicago’s unique culture, traditions and diversity to visitors and residents alike,” Gang said at the time she was selected. “The new Global Terminal and Global concourse is a critical project for unlocking both O’Hare’s potential to be a leader in aviation and Chicago’s future success as a contemporary, economically strong and truly global city.”

Gang is the architect who designed Vista Tower and helped transform Meigs Field into a nature preserve.

The Studio Gang website describes that terminal and concourse: “Like the confluence of the Chicago River, the design’s converging three branches create a central hub that establishes a vibrant new neighborhood in the heart of O’Hare’s campus.”

At the central hub of the global terminal, “a vibrant new neighborhood unfolds around an expansive Central Green that can support pop-up events, music and informal gathering. The plantings extend through the terminal’s three branches, framing boulevards of restaurants, shops and retail that together evoke a lively Chicago street,” the website states.

Earlier Monday, Buttigieg toured the air traffic tower at O’Hare, meeting with workers there. He was also expected to visit the Aviation Institute of Maintenance, 3711 S. Ashland Ave., where he was expected to talk about the importance of strong workforce training programs for the next generation of aviation workers, officials said.