ARLINGTON — A statewide study on airport capacity due to be finished soon seems to support the idea that local airports such as Paine Field, Arlington Municipal and Harvey Field in Snohomish need to plan for some type of expansion.

The report’s line of reasoning, however, is challenged by a group fighting to block passenger flights at Paine Field.

The report, called the Washington State Long-Term Air Transportation Study, is due to be finished in June. A draft now is available for review and input is being sought, officials said.

The report does not make a final recommendation but does make several policy statements and reaches conclusions about capacity.

The report predicts Sea-Tac Airport and three others, including Harvey Field in Snohomish, will reach or exceed capacity by 2030. Paine Field, owned and operated by Snohomish County, and Arlington Municipal Airport are expected to reach 60 percent of their capacities by 2030, the report concludes.

“It’s very clear from the data that there’s a point at which capacity is reached and you have to look at other places for that capacity,” said Everett City Councilman Paul Roberts, vice chairman of the 10-member Aviation Planning Council that is overseeing the study.

“Paine Field has significant unused capacity for that purpose,” he said.

Greg Hauth of Mukilteo, president of Save Our Communities, said the report and an associated questionnaire fail to consider the effects of aircraft noise on nearby communities.

“This survey’s not about balance, it’s how do we protect airports, how do we fund them,” he said.

The study was ordered in 2005 by the state Legislature to assess aviation capacity through 2030. The bill was co-authored by then-Rep. Dave Schmidt, R-Mill Creek, an advocate of passenger service at Paine Field. The state Senate voted 47-0 and the House of Representatives 93-2 to authorize the study.

The report says the state’s population has doubled in the past 30 years and will increase by another 2.5 million, or 40 percent, by 2030.

By then, 12 of the state’s 138 airports, including those listed above, will reach or surpass their ability to move passengers or freight.

Hauth said the report’s method for determining growth and capacity isn’t clear and appears to be based on old information. It doesn’t consider, for example, new technology that allows more aircraft to fly safely in the sky and more people to move through airports more quickly, he said.

“As far as we can see, they really weren’t forward looking on any of that stuff,” he said.

One of the policy statements calls for efficient use of the system and another calls for investment in new technology.

Roberts said the economic downturn is pushing the critical point out a little bit.

“To some degree it’s how good is your crystal ball,” he said. “There’s still a need to look at capacity beyond Sea-Tac.”

Other policy statements in the report include: