CHICAGO (CBS) — The O’Hare International Airport modernization program is a project that’s been years in the making.

But on Friday morning, crews at O’Hare broke ground on the last runway extension.

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Mayor Lori Lightfoot, Senator Dick Durbin and Congressman Raja Krishnamoorthi shoveled ceremonial dirt to kick off the runway expansion.

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“It’s not a coincidence that O’Hare has reclaimed the title of the world’s busiest airport and has held that title of the best connected airport in the U.S. for four consecutive years,” Lightfoot said.

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More than $1 billion has been spent on the project since 2005. The mayor says it’s already decreased flight delays more than 60 percent.