Nearly 19 percent more airline flights took off and landed at Charles M. Schulz–Sonoma County Airport last month than a year before, and almost 15 percent more passengers on those planes, partly thanks to new destinations and carriers, according to figures released Tuesday. But there also were more empty seats.

The Santa Rosa airport (STS) handled 23,572 airline passengers in February, up 14.7 percent from 20,554 a year prior, according to a monthly report from the county of Sonoma, which runs the airport. The report doesn’t include flyers on the several charter services that serve the airport.

The number of flights from Alaska Airlines and newcomers Allegiant Air and American Airlines increased 18.7 percent to 412 last month from 347 in February 2016. Alaska accounted for 370 of those flights, compared with 16 for Allegiant, which cut a Phoenix route Jan. 2, and 26 for American, which started Phoenix flights Feb. 16.

“Load factor” is the transportation industry term that approximates how full planes, trains or buses are with passengers. Alaska Airline’s load factors on Santa Rosa flights in February and the first two months of the year — 74 percent and 70 percent, respectively, on the 76-seat planes — were down about 5 percent from the year before. Allegiant’s 166-seat jets had load factors of 45 percent in February and 54 percent in January–February. For its couple of weeks of Santa Rosa service, American’s 70-seat jets had an 80 percent load factor.

For the first two months of this year, airlines carried 46,599 passengers to and from Santa Rosa, up 15 percent from the same timeframe last year. Such flights totaled 837 in January and February, up 16.9 percent. Alaska Airlines added routes in the past 12 months, and Allegiant started service from Las Vegas and Phoenix-Mesa in May.

United Airlines plans to start three daily flights between Santa Rosa and San Francisco International Airport (SFO) in June. Sun Country Airlines intends to connect start seasonal flights to Sonoma County Airport from Minneapolis–St. Paul airport (MSP) in August.