Agents checked 35 passengers per second as travel surged to a new high on Sunday, July 7.

More than three million people passed through United States airport security on Sunday, the first time that number of passengers have been screened in a single day as travel surges, according to the US Transportation Security Administration (TSA).

The record, which was widely predicted to happen at some point over the Fourth of July holiday weekend, topped the June 23 mark of more than 2.99 million screened passengers. Eight of the 10 busiest days in TSA’s history have come this year as the number of travellers tops levels seen before the COVID-19 pandemic.

TSA was created after the attacks on the US on September 11, 2001, and replaced a collection of private security companies that were hired by airlines. The agency operates under the Department of Homeland Security, which said that agents on Sunday checked 35 passengers every second.

While Americans continue to grapple with inflation, travel costs including airline tickets and hotel prices have eased significantly from a year ago. Hotel rooms were 1.2 percent cheaper in May compared with a year ago, according to recent government inflation data. Those costs have been trending lower since the beginning of the year.

While most US airlines lost money in the first quarter — traditionally the weakest time of year for travel — they were all expecting a summer of full planes.

American Airlines and Southwest Airlines said they expected solid second-quarter profits. They joined Delta Air Lines and United Airlines in giving an upbeat outlook for the April-through-June period, which includes the start of peak season for carriers.

Delta reports its second-quarter earnings on Thursday, with analysts predicting sales of $15.5bn, nearly $1bn more than the same period a year ago. Next week, United and American issue their quarterly results, with Wall Street forecasting higher revenue from a year ago for both carriers.

Increasingly full planes since the pandemic shut travel down four years ago have brought one downside for airlines: complaints.

The US Department of Transportation said last week that it received nearly 97,000 complaints in 2023, up from about 86,000 the year before. The department said there were so many complaints that it took until July to sort through the filings and compile the figures.

That’s the highest number of complaints about airlines since 2020, when airlines were slow to give customers refunds after the pandemic shut down air travel.