BANGOR — Bangor International Airport served more passengers in 2013 than it had in any year since 2005, but the increase couldn’t stave off 25 layoff notices handed out to employees earlier this month.

In 2013, the airport saw 487,775 airline passengers through its terminal, a six percent increase over the previous year’s total of 460,268, according to an airport official.

“We are very pleased with the passenger traffic numbers and thank everyone who used BGR in 2013,” airport Director Tony Caruso said Tuesday. “These strong numbers show that commercial flights to and from Bangor continue to be popular and competitively priced.”

Numbers have been climbing steadily since the airport saw its low point in 2008, when the economic collapse forced airlines to reduce capacity, according to Caruso. That year, 351,807 passengers went through the airport — 38 percent fewer than 2013.

“Unfortunately, these record-breaking numbers came in a year when other business segments declined significantly,” Caruso said.

Earlier this month, 25 airport employees, a mix of 10 full-timers and 15 part-timers, received pink slips. Prior to the layoffs, the airport had 83 full-time employees and 70 part-time, seasonal or on-call employees. Some of the laid-off employees have accepted on-call posts.

While passenger numbers were up last year, the airport has seen a significant drop in the number of military charter flights coming through. The airport has seen a 75 percent drop in the number of military flights since 2010, but the most significant hit came during 2012-2013, when it saw a 55 percent decrease. Revenue declined accordingly. Each time a military flight landed at the airport, BGR took in money for ground handling, passenger handling, gate use, fuel service and maintenance for the planes.

As the U.S. pulls more troops out of the Middle East this year, military traffic is expected to continue to dwindle. The number of military flights varies widely month to month and year to year, Caruso said, but in the past 12 years, more than 6,000 military flights have touched down in Bangor.

The airport’s 2013 fuel sales dropped about 11 percent from the previous year, and total flight operations — the number of takeoffs and landings — decreased 7 percent, Caruso said.

Caruso said Wednesday that he doesn’t anticipate any more layoffs, but the decision will depend largely on what airport officials find when they prepare the budget for the next fiscal year, which starts in July.

Looming on the horizon is another unknown — how the merger between U.S. Airways and American Airlines will affect Bangor. Once the two combine to create the largest airline on the planet, the new company says it expects to fly more than 6,700 flights to 336 destinations in 56 countries per day. However, to get the deal moved forward, the airlines had to agree to divest flight slots to avoid monopoly status.

Where those slots will be lost has yet to be determined, but it’s likely airports in small and medium markets — such as Bangor and Portland, Maine — could be affected.

Caruso said the airport would continue to work to find new sources of revenue, such as the long-term lease that Maine State Police entered last year that allowed its barracks to move from Orono to a renovated former Federal Aviation Administration building on airport property. He also cited C&L Aerospace, which is expanding its headquarters in Bangor, as well as its employment base.