Baltimoreans’ favorite airport is getting bigger.

Come January, passengers traveling through Baltimore-Washington International Thurgood Marshall Airport will notice some additions: new gate areas, an open-concept marketplace and, of course, more of those award-winning bathrooms.

The new concourse A/B connector is the largest single expansion project in the airport’s history since it opened to travelers 75 years ago as Friendship International Airport. Though not adding any new gate capacity, officials say the 142,000 square feet of new space and 78,000 square feet of renovations lay the groundwork for the airport to continue adding more flights and serve more passengers.

Hundreds of domestic and international flights come and go from the BWI tarmac every day, bringing about 27 million passengers through the airport each year. Shannetta Griffin, director and CEO of the Maryland Aviation Administration, which oversees the airport, said she expects to see those numbers grow in the coming years.

“This space allows us to be able to have that growth,” Griffin said as she gave reporters a tour of the new construction Wednesday. She praised the crew for delivering the project on time and on budget, despite the COVID pandemic affecting the planning process.

“This space is very different from anything else in the airport, so they [travelers] know we’re always looking for the best practices, best advancements, best technology, to make sure that we have the best for our community right here in the state of Maryland,” Griffin said.

Construction began in early 2022, and the connector is set to open to the public Jan. 9. The nearly $500 million price tag was covered primarily through state bonds, but did receive about $38 million in federal grants, according to state budget documents.

The new space bumps gates A1 through A5 — the ones down the steps from the Qdoba and other main food court restaurants — further out toward the tarmac, with revamped waiting areas. From there, turn right for a new walkway to the rest of concourse A or left to get to concourse B.

The full length of the new connector took a Banner reporter 295 steps and two minutes, 45 seconds to walk end to end — one should budget more time if carrying a heavy bag or a screaming toddler, or less time if you are sprinting to catch your next flight.

Five gates were shut down for the length of construction, but Griffin said it did not affect the airport’s flight capacity because the other gates could handle the overflow.

The space is lined with more of those fancy bathrooms and space for future restaurants or lounges. Though just a “connector,” planners wanted the space to feel like its own terminal, said Robert Kleinman, who is managing the project — “all to improve the traveler experience,” he said.

And it wouldn’t be BWI without some nice Maryland touches. A few large beams covered in the state flag line the ceiling. The future marketplace area, though only showing a Dunkin Express and Beers of the World bar so far, will soon host local vendors and concessions, Griffin said. As the tour wound down, workers were unfurling a Lexington Market banner on one of the stall walls.

But even more is happening below what the traveling public can see.

The project also totally replaced the “antiquated” concourse baggage handling with a new, state-of-the-art system, Kleinman said. The old system could process about 2,100 bags an hour, he said, while the new one can move 3,400. It could also one day be expanded to handle 5,200 bags an hour.

The system includes 670 motors powering a mile and a half of conveyor belts, shuffling bags the floor below where passengers bustle between gates. The shining blue-and-yellow steel machines resemble industrial-sized Erector sets that can ferry checked bags from plane to carousel in six minutes — faster than at Washington Dulles International Airport.

“It’s our baby,” Kleinman said with a smile.

The new baggage system requires quite a bit of power, Kleinman said, so planners looked for ways to keep the rest of the construction as green as possible. Electrochromic glass on the sides and ceiling of the connector help reflect sunlight and regulate the interior temperature, he said.

Concourses A and B are primarily used by Southwest Airlines, which pilots about 70% of flights in and out of the airport.

BWI is Southwest’s East Coast hub, and the fourth-busiest airport for the Texas-based carrier. The discount carrier has long been considered Baltimoreans’ airline of choice, though it has nixed some of its signature perks in recent years, like free checked bags, much to travelers’ dismay.

Between working with BWI to ensure the connector met their needs to the new maintenance hangar — the airline’s first in this part of the country — Southwest “continues to let us know they’ll be a strong partner,” Griffin said.