Investing.com -- The board overseeing Washington Dulles airport approved a $19.9 billion renovation plan on Wednesday. The project includes $3.75 billion allocated for constructing underground tunnels and replacing the current passenger transport vehicles that move travelers across the tarmac.

The Metropolitan Washington Airports Authority said the $6.2 billion reconstruction of the main terminal at the primary international airport serving the Washington D.C. region will start in late 2027. Construction of new tunnels to eliminate the "People Mover" vehicles and extend to a new concourse is scheduled to begin in early 2029, with completion expected by 2034.

Dulles airport serves as a major hub for United Airlines.