Air travel at local airports continued to slide in September with passenger counts down 13% from August as the summer travel season ended and the Delta variant continued to spread.

The four commercial airports serving Los Angeles County — Los Angeles International, Ontario International, Hollywood Burbank and Long Beach — had 5.4 million passengers go through their gates in September, down from 6.2 million passengers in August, which in turn was down from 6.7 million July.

The September passenger count at the four airports was up 155% from the same month last year though down 34.7% from pre-pandemic September 2019.

Preliminary October passenger boarding data from LAX indicates air travel remains stuck at about the same level, inching up 2% from September but remaining about 35% below pre-pandemic October 2019 levels. Unknown at this point is how the cancellations of hundreds of flights by Dallas-based carrier Southwest Airlines Co. in mid-October impacted the number of travelers.

Another set of flight cancellations from Fort Worth, Texas-based American Airlines Group Inc. hit LAX around Halloween, and the threat of more airline flight cancellations hangs over the holiday travel season.

Yet Justin Erbacci, chief executive at Los Angeles World Airports, the city agency that runs LAX, remains optimistic about increases in passenger traffic during the holiday season. He pointed to the Nov. 8 lifting of Covid-related travel restrictions from many countries, including Britain and the European Union.

Since the pandemic began, international air travel has lagged behind domestic travel at LAX. In September, 731,000 international travelers went through the airport’s gates, down 65% from pre-pandemic September 2019. So, any boost to international flights would be welcomed.

“As we enter the fall and winter holiday seasons, we have a number of reasons to be optimistic about an increasing return to air travel, including the highly anticipated reopening of the U.S. border to additional international travelers on Nov. 8,” Erbacci said. “We also are expecting the airlines to operate significantly more flights this November compared with 2020.”

Meanwhile, at the region’s secondary airports, Ontario International continues to be the performance star. While passenger traffic dipped almost 5% between August and September to 453,000, it is only down 3.4% from pre-pandemic September 2019, meaning the airport has recovered nearly all the passenger traffic lost during the Covid shutdown.

On the cargo side, tonnage at the four airports rose 3.25% in September to about 320,000 tons.