KENNEWICK — Port of Kennewick commissioners had a hard time swallowing the amount it would cost for Mike Shannon to operate Vista Field Airport.

Shannon's proposal could run between $20 million to $33 million during the 30 years of the contract, port staff said Tuesday.

That's a huge change from the $40,000 a year Shannon, who owns Kennewick's Shannon Dental, initially indicated he would want the port to pay for airport operations, staff said.

Port staff have been negotiating an agreement with Shannon for him to take over as the Vista Field fixed-based operator since fall.

Port commission President Skip Novakovich said he was disappointed that Shannon's most recent proposal was so far off from what commissioners thought it would be.

"I was just kind of shocked," he said.

Finding that kind of money for the airport would mean having to raise taxes, staff said.

But Novakovich said he isn't sure taxpayers would be willing to pay higher taxes to keep the airport open.

Tammy Fine, the port's finance director and auditor, said staff will look into what tax increase options exist. She also wanted more time to review the proposal and to meet with Shannon to clarify some of the details.

The estimated cost to the port would include paying Shannon a management fee that would start at $60,000 a year and contributing toward capital improvements each year, said Port Executive Director Tim Arntzen.

Arntzen said while the proposal differs from earlier discussions, it's likely a candid private-sector analysis of what it would take to make Vista Field viable.

Arntzen said the port has struggled with the airport for the last decade. Each year, taxpayer money is used to subsidize the airport.

Port commissioners decided to keep Vista Field open in 2010 after hearing from the public, including some who said private investment would come to the area based on Vista Field being open.

If Shannon's proposal is really what it would take to operate Vista Field, Novakovich said commissioners will need to think hard.

Taxpayers might change their mind about keeping the airport open if they know how much taxes would increase to pay for the airport, Novakovich said. An exact tax increase was not discussed.

Ed Frost of Kennewick told commissioners that if it comes down to raising taxes, voters should weigh in.

There also needs to be factual data on the actual use of Vista Field for the decision-making process, he said.

Port Commissioner Gene Wagner said the port should not be spending more than $30,000 a year to keep the airport open. Vista Field has done nothing but suck money from the port, he said.