California is the most populous state in the United States, with approximately 40 million residents. When it comes to air travel, there are numerous airports to choose from within the state. One prominent regional airline, SkyWest Airlines, operates on behalf of major carriers such as Delta, Alaska, and United Airlines, providing essential connectivity between key cities. This raises the question: What are the top ten routes operated by SkyWest Airlines?

SkyWest Airlines operates a fleet of Embraer E175 aircraft, making this analysis unique as all the listed flights are operated by this type of aircraft. The E175 is well-suited for regional conditions and is the largest fleet among all regional airlines in the United States. Due to scope clause requirements from mainline partner carriers, regional airlines are limited in the size of aircraft they can operate, based on overall seat capacity. The data used in this analysis was sourced from Cirium, an online aviation analytics company, and is based on May 2025 figures.

10.

United Airlines, part of the Star Alliance group, uses SkyWest’s E175 to operate flights between San Diego and the bustling city of Los Angeles under the United Express banner. With its central downtown airport location, passengers on these flights can enjoy stunning views of the San Diego skyline during take-off and landing. San Diego is a popular destination for both tourists and business travelers.

In May, SkyWest will operate 110 flights on behalf of United Airlines, averaging four flights per day and 25 flights per week. The United Express configuration for this route includes 12 first-class seats, 16 or 32 economy plus seats, and 26 or 48 economy seats.

Average flights per day: 4
Average flights per week: 25
Flights this May: 110
Average seats per week: 1763
Seats this May: 7808
Available seat miles for May: 850,418
Total flight distance: 109 miles

This route is unique as it is the only service operated by SkyWest, under the United Express brand, to this airport. United Airlines also operates direct flights to Chicago–O’Hare, Denver, Houston–Intercontinental, Newark, San Francisco, and Washington–Dulles, but these are all operated by their mainline fleet. In contrast, their flights to Los Angeles are operated by United Express.

9.

Alaska Airlines faces tough competition on their route between Sacramento and San Diego, going head-to-head with low-cost carriers Frontier and Southwest Airlines. SkyWest’s E175 operates flights on behalf of Alaska Airlines, connecting the two cities up to four times a day on select days of the week.

In May, SkyWest will operate 112 flights on behalf of Alaska Airlines, providing up to 8500 seats each way.