What major expansions has the Seattle-Tacoma International Airport undergone?

Detailed answer

The Seattle-Tacoma International Airport has undergone several major expansions over the years, including the addition of a new terminal building, concourses, and parking garages. One notable expansion was the construction of the third runway, which was completed in 2008 and has significantly increased the airport's capacity to handle air traffic. The airport has also invested in upgrading its facilities, including the installation of new security screening equipment and the renovation of existing terminals.