(Commonwealth News Service) The number of people who traveled on U.S. airlines last year remained below pre-pandemic levels but consumer complaints about the airlines nearly quadrupled compared with 2019. 

A new report compiling data from the Department of Transportation shows travelers' top complaints related to flight delays or cancellations and a lack of refunds. 

Massachusetts Public Interest Research Group Consumer Program Director Deirdre Cummings said airlines are making short-sighted decisions about staffing and scheduling, leading to a surge in complaints.

"While there was a slight drop from 2021," said Cummings, "it's still ten times more the number of complaints about refunds compared to 2019."

Airlines canceled more than 190,000 flights last year, or nearly 3 percent of all flights scheduled. 

The data compiled does not include the month of December - when thousands of flights were canceled, causing so many complaints that they couldn't be tallied in time for the year-end report. 

The airlines are now gearing up for the busiest travel season in four years, with some 78 million passengers projected in April. 

Another top complaint among travelers has been lost or damaged luggage, including wheelchairs and scooters. Cummings said federal officials need to step up their game to protect air travelers.

"It really comes down to how the airlines are running their operation," said Cummings, "and then what sort of oversight is there and what sort of penalties."

Cummings said while travelers can protect themselves by paying with a credit card, or traveling earlier in the day - the Department of Transportation has proposed some fixes including an online dashboard to view airlines' policies prior to booking and requiring airlines to inform passengers whose flights are canceled that they are entitled to a full refund.