EVERETT — Horizon Air, which proposed running 140 commuter flights a week from Paine Field, says it is no longer interested in serving the Snohomish County airport.

The announcement comes on the heels of the release of a report Friday addressing the environmental effect of those flights and 20 more per week proposed by Allegiant Air of Las Vegas — rendering that report already outdated.

Horizon, a subsidiary of Alaska Airlines of Seattle, and Allegiant Air asked Snohomish County in 2008 for permission to fly from the airport.

“A lot has changed in the last couple of years,” Horizon spokeswoman Bobbie Egan said.

The economic recession and improvements made at Seattle-Tacoma International Airport were the major factors in the decision, she said. She added, however, that the airline could reconsider in the future.

Allegiant proposed to start running four flights per week from Paine Field and increase to 20 over five years, said Keith Hansen, director of airports for the airline.

Allegiant continues to be interested in flying commercial flights out of the airport, he said.

It’s unclear whether Horizon’s withdrawal will require the FAA and Snohomish County to redo the report that took three years and more than $600,000 in public funds paid to consultants to assemble.

The report concludes that the combined Horizon and Allegiant flights would have no significant effect on noise, traffic or air quality in neighborhoods around Paine Field.

Written comments will be accepted through Oct. 14. Officials with the FAA said the agency would decide by the end of the year whether Horizon and Allegiant could serve the airport.

“We still have a process to go through,” FAA spokesman Allen Kenitzer said Friday, declining to comment further on Horizon’s decision.

Jets at Sea-Tac began using a new third runway in 2008, Egan said. Also, in the past few years, the Sea-Tac terminal and rental-car area were remodeled and Sound Transit light rail recently began serving the airport.

“Just the significant investments made at Sea-Tac the last couple of years lead us to feel strongly that Sea-Tac is the best airport to serve our region,” Egan said.

Horizon operates commuter flights from 41 airports, including Bellingham. The airline recently began service from San Diego to Monterey, Santa Rosa and Fresno in California, Egan said.

Hansen said while Allegiant still wants to serve Paine Field, it’s not certain it would be at the level originally proposed.

“We’re talking a different economy today, it’s four years later,” he said.

The airline currently serves 88 airports and runs 33 flights per week from Bellingham, up from six per week in 2004.

What Allegiant would likely do at Paine Field, he said, is “consistent with what we have done at other markets, which is kind of start small and look to grow.”

He added that he was pleased that the report showed no negative effect from airline operations.

Local supporters of commercial flights hailed the completion of the final environmental report and said it’s time to proceed. Opponents said the study was flawed.

The report addresses more than 900 comments made in early 2010 on the first draft of the study.

At first, the FAA said its response to the comments would be out in two months, but it took much longer — more than 2½ years. Officials said the delay was primarily because of staff time needed on other projects and a need to be thorough in responding to the comments.

Internal FAA emails, however, suggested politics may have contributed to the delay.

In a February 2012 email to managers, an FAA environmental protection specialist attributed the delay to “poor performance on the consultant’s part, need to further analyze airport capacity, and a sponsor’s desire to not have this become an election issue.”

The sponsor is Snohomish County. County Executive Aaron Reardon has said he opposes passenger flights at the airport, but his staff said they did not interfere with the process.

The county originally hired Barnard Dunkelberg Co., an aviation planning firm with offices in Tulsa, Okla., and Denver, Colo., with FAA approval. That firm this year merged with engineering firm Mead &Hunt, headquartered in Madison, Wis.

As of late last month, the consultant had been paid $654,000, with $608,000 directly from the FAA, according to Paine Field director Dave Waggoner.

Egan said the delay itself was not the reason for Horizon’s decision. The fact that the report took three years to complete, however, allowed other changes to occur in the meantime, she said.

“Where we are in this industry, in the current economic recession, things always change,” Egan said.

Still, the airline is leaving the door open for coming to Paine Field in the future. If another airline were to begin flights here, then Horizon would have to reconsider from a competitive standpoint, she said.

If Allegiant is granted permission to fly from Paine Field, and does so, then the net result could be the same as the original plan.

“If a competitor commits to serving Paine Field we would have to respond by adding flights,” she said.

But for now, Egan said, Horizon is out of the Paine Field sweepstakes.

Reporter Noah Haglund contributed to this story.

Bill Sheets: 425-339-3439; sheets@heraldnet.com.