Sonoma County Airport Plans 15-Year Expansion as Passenger Traffic Hits Records
Why It MattersGeneral-aviation airports facing scheduled-carrier growth must sequence terminal, parking and apron upgrades separately, since each project carries its own funding and approval timeline rather than a single capital plan.
What happened
Charles M. Schulz–Sonoma County Airport is developing a 15-year expansion and modernization program as passenger traffic reaches record levels and strains parking, terminal space and other facilities. Airport Manager Jon Stout told the Sonoma County Aviation Commission on Thursday that consultants Mead & Hunt are coordinating 13 potential projects around the terminal, including a consolidated rental car facility, parking changes, roadway improvements, new hangars and relocation of airport offices. "Right now, this is just a conceptual discussion on paper," Stout said, noting no phasing or funding commitments have been adopted for many of the projects, with each requiring its own planning, environmental review, budget and approval process.
The airport handled 95,732 passengers in July, up 24.2% from a year earlier. Through July, total traffic reached 505,157 passengers, 10.4% above the same period in 2025, while airline arrivals and departures rose 15.4% year to date to 7,528 flights. Alaska Airlines carried 60,612 passengers in July, American Airlines carried 13,945, and Southwest Airlines, which began Santa Rosa service in April, carried 21,175 passengers with a load factor of 68%. Rental car revenue reached $2.07 million in June, up 27% from June 2025.
Among the more advanced plans is a consolidated rental car quick-turnaround facility, with design targeted for this fiscal year and construction potentially starting no earlier than next summer or fall; associated changes would redirect rental car and parking traffic toward Ordnance Road and could add a two-lane roundabout at its junction with Airport Boulevard. Another concept would relocate airport administration into two former North County Detention Facility buildings north of the terminal, contingent on the Sheriff's Department not returning those facilities to jail use within two or three years, at an estimated renovation cost of $4 million to $5 million. The airport has raised daily parking rates by $2, moved employees to off-site lots, and is negotiating with county agencies for temporary use of 220 spaces at twin buildings at 3850 and 3880 Brickway Blvd., which the county approved purchasing and renovating for $47 million in July 2025. Construction is under way on the airline apron, with heavy construction beginning Aug. 3, paving expected to start Aug. 21 and conclude by early October, and the broader project aiming to increase aircraft parking positions from four to six while adding passenger canopies, with construction continuing through 2027. A new wildlife-exclusion fence and apron pavement preservation work are scheduled for Board of Supervisors consideration on Sept. 15, and preliminary engineering is under way for a future rehabilitation of Runway 14/32, with construction targeted for 2029. Commissioners also acted Thursday on two proposals aimed at reducing aircraft noise, including a seven-part, 12-month voluntary Fly Quiet program.
How it unfolded
Construction is targeted for the rehabilitation of Runway 14/32.
The broader apron project, increasing aircraft parking positions from four to six, continues.
Construction on the consolidated rental car facility could potentially begin, at the earliest.
Apron paving is expected to conclude.
A new wildlife-exclusion fence and apron pavement preservation work go before the Board of Supervisors.
Paving on the airline apron is expected to start.
Airport Manager Jon Stout briefed the Sonoma County Aviation Commission on 13 potential expansion projects and two noise-reduction proposals.
Heavy construction began on the airline apron project.
Industry impact & what to watch
This case shows how a general-aviation-turned-scheduled airport absorbs a fast run-up in airline traffic: growth arrives faster than terminal, parking and curb infrastructure can be replanned, so operators lean on interim fixes such as rate increases, off-site employee parking and borrowed spaces at nearby county buildings while formal capital projects work through separate environmental and budget approvals.
At airports of this size, each project competes on its own timeline rather than under a single capital budget, which is why the rental car facility, the apron expansion, the administration relocation and the runway rehabilitation each carry different target years stretching from next year to 2029. That staggering means near-term relief for congestion depends on the fastest-moving pieces, particularly the apron paving finishing by early October and the rental car facility's design phase this fiscal year.
What happens with the Sheriff's Department decision on the detention facility buildings within the next two or three years will determine whether the administration-relocation concept, and the short-term parking it would free up, moves forward at all.
