As the final stage of San Francisco International Airport's $4.1 billion 10-year capital improvement plan, Terminal 1 is getting partially demolished in favor of two new boarding areas, a central check-in and security space, and new baggage claim and mezzanine areas.

The Business Times had word that construction will begin on June 29 and last until 2020. A temporary boarding area is opening this month to serve the domestic airlines typically housed in the terminal: Delta, US, Alaska, and Frontier.

The most recent renovation, the penultimate of the capital improvement plan, was completed this year: That was of Terminal 3, and it added three more boarding gates and streamlined, centralized security. Previous to that, Terminal 2 renovations were completed in 2011, bringing more dining options, two yoga rooms, and a "recomposure zone."

SFO saw 50 million total passengers in 2015, its most ever in line with record tourism numbers in San Francisco overall that year. Meanwhile, the Mercury News reported earlier this month that Oakland is also at work increasing its number of nonstop flights to Oakland International Airport.

Related: Virgin America To Remain Its Own Separate Brand For Now, Maybe Forever