Bozeman Yellowstone International Airport just hit a new milestone: busiest airport in the state.

The Montana Department of Transportation released statistics last week showing that with 879,221 passengers passing through the airport’s terminal between June 2012 and May 2013, it surpassed all other airports statewide.

In three years, passenger traffic has increased 28 percent or nearly 200,000 passengers, Airport Director Brian Sprenger said in a prepared statement. Much of the influx has been due to additional nonstop flights to Portland, Ore.; Los Angeles; Phoenix; and Newark, N.J. The addition of low-fare airlines Frontier and Allegiant Air also contributed to the growth.

With runway construction getting under way this summer at the Billings airport – previously the state’s busiest – Bozeman airport officials expected to surpass Billings’ numbers.

“We knew we’d beat them because of the runway construction,” Sprenger said Monday. “But to actually beat them before that started was a surprise.”

And Sprenger anticipates the airport to remain busy.

A $950,000 federal grant and a $750,000 local business match intended to entice United Airlines to run direct flights between Bozeman and Newark has been in place for more than a year and will be available for more than another year. The flight serves the New York City market. The money is used if United does not make a minimum income from the flight.

After adding a weekly Sunday flight to an existing Saturday flight, about $750,000 of the federal funding still remains unused, Sprenger said. He hopes United will add a third weekly flight to Newark.

“We probably won’t use the entire grant because the flights have been more successful than even the airline expected,” he said. “That gives us hope that they’ll be able to expand” the service.

Debbie Youngberg, executive director for the Belgrade Chamber of Commerce, said with increased passengers coming through the airport and the soon-to-be-built Interstate 90 interchange to the airport, Belgrade should see positive economic benefits. The city’s tax revenues should increase with visitor traffic to local retailers, hotels and restaurants and with the potential for new manufacturing and other businesses.

“What’s good for the airport is good for everybody,” she said. “I truly believe Belgrade’s going to explode. We are going to grow our business district, definitely. I just think it’s going to be a win-win situation for everybody.”

More than 500 people are employed with 28 businesses at the airport.

When asked about the airport infrastructure’s ability to handle increased traffic, Sprenger had few concerns.

Recent additions to the terminal are designed to handle up to 2 million monthly passengers.

And though Bozeman has a single runway to handle commercial traffic, even San Diego’s airport handles more than 20 million passengers with a single runway. And more passengers doesn’t equate to more flights, only larger aircraft.

“So we’ve got a long way to go before we have concerns about that,” Sprenger said.

He said the new milestone as the busiest airport is a result of collaboration between the airport and the communities of Bozeman, Belgrade, Big Sky and West Yellowstone. Long-term partnerships with Montana State University, the Yellowstone Association and the Yellowstone Park Foundation were also instrumental.

“We are fortunate to have so many entities in southwest Montana that understand the importance of air service to the local economy,” Sprenger said. “Without their help, we would not be celebrating this momentous occasion.”

Jodi Hausen can be reached at jhausen@dailychronicle.com or 582-2630. Follow her on Twitter @JodiHausen or on Facebook at Jodi Hausen, journalist.