At the current pace the airport should see about 300,000 boardings this year, down from 331,000 last year and the first decline since 2009.
The Tri-City Herald reports the airport needs at least 251,000 boardings to provide revenue for a terminal project that would be funded in part with bonds repaid by passenger charges.
Airport Director Ron Foraker says boardings have dropped because of Hanford layoffs, federal spending cuts and some airlines offering fewer flights.
Direct flights to Los Angeles were canceled in August, and San Francisco, Minneapolis and Denver flights were reduced during the winter months. All but a Minneapolis flight have resumed, and that flight should be back in May.
Port staff say that even if boardings fall to as few as 251,000 this year, there would be enough airport revenue for the airport terminal project.
The number of boardings affects the amount of airport improvement program money received from the Federal Aviation Administration and the passenger facility charges collected from airline tickets.
"We are still planning on doing the whole project if possible," said Linda O'Brien, the port's finance and administration director.
Port Executive Director Jim Toomey said the port will likely issue the bonds in the next 12 months. Port staff will continue to monitor boardings and revenues, and the commission could still decide to do the project in phases.