California boasts hundreds of miles of coastline, dozens of national and state parks, and world-famous cities such as Los Angeles, San Diego, and San Francisco.
It’s no wonder that domestic airlines are duking it out for market share in these affluent and massive metro areas, but one turf war in the state is happening somewhere decidedly less obvious: among the vineyards.
Delta begins first-ever service to Sonoma County
Last week, Delta Air Lines touched down for the first time in Sonoma County Airport (STS), an airport located approximately an hour’s drive north of San Francisco. It marked the first service to the airport in Delta’s 101-year history, but for decades, it has provided a direct gateway for travelers to get to one of the world’s predominant winegrowing regions.
The twice-daily nonstop service on an Embraer E175 will connect Delta’s Salt Lake City hub with California’s famous Wine Country and Redwood Coast, including the cities of Santa Rosa, Napa, Sonoma, and Healdsburg. Delta’s entry will offer visitors (and locals) an alternative to San Francisco International Airport (SFO), which is nearly 75 miles south of the airport.
Sonoma has been a revolving door for airlines
While local heavyweight United flew Sonoma County Airport’s first jet service in 1989, it withdrew by 2001, leaving the airstrip without a commercial carrier for six years.
In 2007, Alaska Airlines revived the airport’s commercial service, a move which has helped solidify it the runaway leader at the airport. For nine years, Alaska held the fort down with the help of regional carrier Horizon Air.
However, since 2016, the airport has seen a revolving door of different airlines try to put down roots. Some have been mainline offerings, while others have been through regional carriers. Not everybody has been equally successful:
- Allegiant: Operated a brief service from May 2016 to June 2017
- American Airlines: Resumed service after a 24-year break from the airport in 2017.
- United: From Jun, 2017 to Oct. 2022, United Express returned with a short hop to SFO, helping locals get to its primary hub.
- Sun Country Airlines: Gave it a go from Aug. 2017 to Mar. 2020, stopping service just before the Covid-19 pandemic ravaged the airline industry.
- Avelo: From Apr. 2021 to Aug. 2025, the low-cost carrier showed glimmers of strength and even had jets based at the airport.
- Southwest: Began service in Apr. 2026.
In that context, Delta’s arrival comes just months after Southwest began flying nonstops. However, it’s possible that Delta was moved to action by the airport’s dominant airline, Alaska. In May, Alaska announced three new seasonal routes from Sonoma County Airport, including Boise, ID (BOI), Phoenix (PHX), and notably, Salt Lake City (SLC).
It didn’t take long for Delta Airlines to announce it would start its own service out of its SLC hub. Ironically, Alaska would go on to cancel its STS-SLC route, along with a route to Ontario, CA amid higher fuel costs.
Airlines vie for Wine Country dominance
In 2025, over 54 million passengers transited San Francisco International Airport. Neighboring Sonoma County (STS) saw just 780,000 passengers. That means that SFO saw approximately 70x more customers.
But for Alaska, American, Southwest, or Delta, foot traffic isn’t the point. None of these four carriers command a significant share at SFO, where United made up 48.7% of domestic and international seats. Together, those aforementioned four carriers make up about 28% of seat share from the airport.
Instead, it’s about convenience.
Sonoma County Airport isn’t a replacement for SFO, but a more compelling offering to get locals and tourists to their final destinations.
For locals, the pitch is simple: Affluent Sonoma County residents can skip a long drive to SFO or Oakland International Airport (OAK). Airline tickets might be modestly more expensive, but that might be a small price to pay to avoid an expensive rideshare to the airports down south.
For tourists and visitors, the pitch is equally simple: You can get directly to Wine Country and the Redwood Coast. That’s not just the case for California-based travelers flying between different metros, but for an increasing number of out-of-state destinations like Seattle, Denver, and Dallas, among others.
That’s a hard pitch to beat, too. There’s evidence that’s already working, even, as year-to-date traffic through August 2026 hit 601,362, which represents an 13.6% increase year-over-year.
