U.S. Transportation Department officials last year were up to their necks in complaints submitted by air travelers over everything from delays and cancellations to accommodations for disabled passengers.   

The agency reported on Friday that it received nearly 97,000 submissions in 2023, 91% of which were complaints. That’s up from about 86,000 total submissions, including complaints, inquiries and opinions in 2022. 

The department said there was such a high volume of consumer grievances filed against airlines and ticket agents last year that it took until this month to sort through the filing and compile final figures.  

The figure marks the largest number of air travel complaints by consumers since 2020, when airlines were slow to give customers refunds after the coronavirus pandemic shut down air travel. That year, the department received roughly 103,000 complaints, according to PIRG.

The increase in complaints came even as airlines canceled far fewer U.S. flights — 116,700, or 1.2% of the total, last year, compared with about 210,500, or 2.3%, in 2022, according to FlightAware data. However, delays remained stubbornly high last year, at around 21% of all flights.

So far this year, cancellations remain relatively low — about 1.3% of all flights — but delays are still running around 21%.

More than two-thirds, or 67,661, of submissions last year dealt with U.S. airlines, but a quarter, or 24,991, covered foreign airlines. Travel agents and tour operators were the reason for 3,162 complaints.

Disability-related grievances rose by more than a quarter compared with 2022, with some incidents making headlines, including a paraplegic Delta Air Lines passenger in December 2023 who claimed he was forced to crawl to his Delta Air Lines seat after no one was available to help him board. Earlier that year in November, a video went viral of American Airlines crew members mishandling a passenger’s wheelchair, sparking some people with disabilities to speak out about their negative travel experiences. 

Though they would like to travel by plane, many disabled Americans forego air travel out of fear of not being sufficiently accommodated by airlines, according to an April study from the Century Foundation. 

Complaints of discrimination, while small in number, also rose sharply. Most were about race or national origin.Airlines receive many more complaints from travelers who don’t know how or don’t bother to complain to the government, but carriers don’t release those numbers. 

The Transportation Department said it is modernizing its complaint-taking system, which the agency says will help it do a better job overseeing the airline industry. However, the department now releases complaint numbers many months late. It did not issue figures for the second half of 2023 until Friday.

— The Associated Press contributed to this report.