Although Washington Dulles International Airport is 10 times its size, Reagan National Airport carried 1.6 million more passengers last year—and eight million more than it was originally designed to handle.

To better accommodate the masses, the Metropolitan Washington Airports Authority is undertaking a $1 billion overhaul starting this summer, and it will mean some major changes. Most notably, the plans call for a new security screening hall (above the arrivals roadway outside of terminals B and C) and replacing Gate 35X with a brand new concourse.

The new security checkpoints will come first. Due to be completed in 2020, they will put the soaring, glass-enclosed main hall beyond the reach of the general public. But once travelers clear security, they will have access to all the airports terminals and amenities. The checkpoints will also increase the number of security screening lanes from 20 currently to 28, according to MWAA.

The new commuter concourse is expected to be finished in 2021, eliminating need for Gate 35X—where flyers currently board buses to get to their plans. It will have 14 new gates and architecture in keeping with the main hall and terminals B and C, including huge windows with views of D.C.

Ridiculous name (“Project Journey”) aside, the overhaul is a dramatic remaking of DCA, and it is long overdue. For the sixth year in row, DCA hit a new passenger record in 2016—recording 23.6 million passengers (for comparison, Dulles was around 22 million and BWI carried 25.1 million). The airport is designed to handle about 15 million people. The changes don’t include any additional capacity for more aircraft.

Still, there will be a few years of disruptions before we get there. Construction of the security checkpoints, starting this summer, will mean significant impacts on the roadways outside the airport. Work on the new concourse, which is set to begin in 2018, will be much less disruptive though, since it is happening outside the building.