Glacier Park International Airport accommodated more than 600,000 inbound and outbound passengers in 2018, once again breaking its annual record as tourism continues to grow as an economic backbone in the Flathead Valley.

The outbound passenger count climbed to 307,000 travelers in 2018, up 13.6 percent from 2017.

The report shows airport traffic peaked during the summer with nearly 50,000 passengers boarding planes in July. Even during November, the slowest month, 16,436 passengers boarded planes at Glacier Park International. Passenger volumes have increased by 33 percent in the last five years.

And airport officials don’t anticipate a drop-off in passenger numbers.

“We’re seeing more passengers come through our doors than ever before, and all projections indicate that those numbers will continue to rise,” Rob Ratkowski, director of Glacier Park International, said in a statement. “The airport is in the process of expanding to meet the demands so it can grow in step with the Flathead Valley. It’s an exciting time for us.”

Although he couldn’t provide passenger projections for the coming year, Ratkowski said 2019 will most likely be another strong year, especially with the addition of new routes.

In the last six months, American Airlines expanded its direct flight offerings to include Chicago, Los Angeles and Dallas. Most recently, Allegiant Air came on board with a direct flight to Phoenix.

Ratkowski said the add-ons have set Glacier Park International on par with most other major airports in the state in terms of route offerings.

To cushion the growth, the airport plans to add 40,000 square feet to its existing terminal, which will expand the ticketing, baggage and waiting areas and will provide space for additional gates.

The expansion will take place over the next three to four years and is part of the Flathead Municipal Airport Authority’s 20-year master plan for long-term development at the airport.

“It’s clear that we need more of everything to keep providing exceptional service to our guests, both local and visitors,” Ratkowski said.

The additional space is expected to comfortably accommodate passenger growth for the next decade, at least. The contract for the preliminary design was signed last week and according to Ratkowski, the layout will better serve the airport’s carriers by providing them designated gates.

“We are hoping to break some space out so everyone has a more dedicated area instead of carriers clamoring for a gate,” Ratkowski said. “The only real limitation will be how many planes the airline wants turn in a day.”

He said design will allow for easy expansion down the road, making further projects more “scalable.” Planning for design and funding will take about 18 months, with construction expected to tentatively begin in the fall of 2020.

In the meantime, airport staff is preparing for the coming busy months as Glacier National Park, which welcomed about 3 million visitors in 2018, remains a focal point for many travelers.

“I have to give kudos to my people,” Ratkowski said. “We continue to go strong and are ready for the summer season.”

Reporter Kianna Gardner can be reached at 758-4439 or kgardner@dailyinterlake.com.