BANGOR, Maine — Bangor International Airport had the best June in years this past month and also saw a strong first half of the year, but BIA Director Tony Caruso says he’s not about to put things on autopilot.

“I think this is our best June since 2005, so we’re very pleased with these numbers,” Caruso said. “But that also means we have to continue working just as hard or harder to build on this success.”

Caruso provided Bangor city councilors with a monthly passenger statistics report during a council airport committee meeting Monday evening at City Hall.

Bangor’s airport has seen a 19 percent increase in total passenger volume — the total number of departing and arriving airline passengers — so far this year and a 12.6 percent increase in June of this year over June 2011.

Through June of last year, 183,280 passengers arrived at and departed from BIA. Through June this year, that total is 218,116. The June 2011 total was 35,569, while this past June’s total was 40,039.

There are other encouraging numbers in the report.

“The other number we look at is load factors, which is the number of people per plane,” he said. “Allegiant [Air] is averaging 89 percent, Delta [Airlines] is 86 and US Airways is 79.

“Those are strong numbers showing we have good demand for travel in and out of Bangor and the service is being supported by people in this region.”

The airport itself has also undergone growth in recent months.

Caruso is especially pleased by the passenger growth BIA has seen over the past several months, but isn’t planning a celebration anytime soon.

“I’d say I’m cautiously optimistic as we continue to watch these numbers, especially with the volatility of the fuel market, continuing airline capacity reductions, and ongoing possibilities of airline mergers.”

A case in point is Delta’s recent announcement that it’s planning to shut down regional subsidiary airline Comair.

“There are occasions where a Comair flight comes into BIA, but that move has a limited to almost no effect on us,” Caruso said. “I believe it’s been several years since we had Comair operating on a regular basis here at BIA.”

Caruso said BIA is primarily served by other Delta affiliates including GoJet, ExpressJet, and Chautauqua Airlines.

Delta and U.S. Airways are competitive in the Bangor market, with Delta holding 46 percent market share and U.S. Airways holding 44 percent. Allegiant holds 11 percent of the passenger market share.