Consumer surveys have shown that, destination aside, the most important factor in buying an airline ticket is price.

So a 5 percent drop in domestic airfares during the first 10 months of 2015 compared with the same period last year should have resulted in lots of happy fliers, right?

Not so. Instead, complaints against airlines are on the rise.

The drop in domestic airfares was reported last week by travel giant Expedia with help from Airlines Reporting Corp., an Arlington, Va., company that handles ticketing transactions between the nation’s airlines and travel agents.

The study of more than 10 billion ticket transactions recorded an 8 percent drop in airfares worldwide. (The Expedia study did not list the dollar price for the average domestic airfare.)

A number of factors have contributed to the average 5 percent drop in fares in North America, including a steep decline in fuel prices.

But rather than singing the praises of airlines over lower fares, passengers are complaining at a 36 percent rate higher than last year, according to consumer data from the federal Aviation Consumer Protection Division.

In raw numbers, the U.S. Department of Transportation received 10,444 complaints against U.S.-based airlines in the first 10 months of 2015, compared with 7,467 in the same period last year. When calculated against the total number of air travelers, the rate was 1.97 complaints for every 100,000 fliers in the first 10 months of 2015 compared with 1.44 in the same period last year.

Paul Hudson, president of flyersrights.org, a nonprofit passenger rights group, said he isn’t surprised at the rise in complaints because airlines continue to charge high fees to check bags and change reservations while packing more passengers into smaller seats.

“The service level has dropped,” he said.

Airline industry representatives played down the complaint rate and instead focused on the decline in airfares.

“The customer complaint rate remains remarkably low,” said Vaughn Jennings, a spokesman for Airlines for America, a trade group for the nation’s biggest airlines. “Air travel remains one of the best consumer bargains out there.”

———

Hugo Martin, Los Angeles Times