(NewsNation) — Fourth of July travelers stuck in long lines and congested airports see new delays and cancellations Monday as the busiest travel weekend since the pandemic comes to a grand finale.

As of Monday morning, airlines within the U.S. have canceled 164 flights and delayed almost 800 flights, according to tracking service FlightAware. Airlines worldwide have canceled almost 1,500 flights and delayed more than 13,000 flights.

The Transportation Security Administration tweeted a travel update Sunday, revealing that TSA screened a total of 2,160,542 individuals on Saturday, July 2. FlightAware reported that airlines had canceled 655 flights on Saturday, and delayed 5,882 flights at U.S. airports.

About 2.49 million passengers went through security checkpoints at U.S. airports Friday, surpassing the previous pandemic-era record of 2.46 million reached earlier in the week, according to figures released Saturday by TSA.

“We are back to pre-pandemic checkpoint volume,” TSA spokesperson Lisa Farbstein tweeted.

The escalating numbers show leisure travelers aren’t being deterred from flying by rising fares, the ongoing spread of COVID-19 or worries about recurring flight delays and cancellations.

Friday’s passenger volume marked a 13% increase from July 1 last year, which fell on the Thursday before Fourth of July. This year’s number of passengers going through U.S. airports also eclipsed the 2.35 million screened at security checkpoints on the Friday before the Fourth of July in 2019, but that was nearly a week ahead of Independence Day.

But airlines have struggled to keep up with the surging demand amid staffing shortages and an assortment of other issues that have resulted in recurring waves of exasperating flight delays and cancellations that have been transforming some vacations into nightmarish ordeals.

Pilots say they’re working longer hours and facing fatigue, leading hundreds from Delta Air Lines to protest, seeking better pay and improved schedules.

Many airlines, including Delta, Southwest and JetBlue, have responded to the challenge by curtailing their summer schedules in an effort to reduce the inconveniences — and backlash — caused by flight delays and cancellations. They are using larger planes on average to carry more passengers while they scramble to hire and train more pilots. Some airlines have ended some services all-together.

Several airlines trimmed summer schedules, but another source of frustration for travelers is airlines overbooking flights.

Legally, airlines can oversell or overbook flights. In fact, they do it all the time, and the airlines are not required to tell you ahead of time if the flight is overbooked. Passengers can ask, but usually travelers don’t find out they’ve been bumped off a fight until it’s time to check in.

Delta even offered passengers $10,000 to give up their seat on a recent flight.

This weekend, American Airlines suffered a major technical glitch Friday in which allowed pilots to drop up to 12,000 flights throughout July, the Hill reported. Since the glitch scare, the airlines told the Hill that they had already restored the “vast majority” of flights affected and that they don’t expect any additional issues from the incident.

On Friday, there were more than 6,800 flight delays and another 587 flight cancellations affecting U.S. airports Friday, according to the tracking site FlightAware.

Besides the flight delays and cancellations, travelers also have had to pay higher prices for tickets driven up by soaring fuel costs and other inflationary factors, as well as navigate around the health risks posed by continuing COVID-19 infections.

Travel experts are warning: if you’re getting on a plane, have your Plans A, B and C ready to go. Another good rule of thumb is to download the airline’s app on your cellphone and you can work on rescheduling any potentially canceled flights right from your phone.

“It’s a high-stress time for everyone, pilots, flight attendants,” Clint Henderson, managing editor of news at travel website The Points Guy, said.

And it’s not just air travel, as more than 48 million people are expected to travel at least 50 miles or more from home over the holiday weekend, 42 million of those people are expected to travel by car, according to AAA.

“Maybe people are changing their vacation style right now because everything is so much more expensive,” said AAA spokesperson Andrew Gross. “Folks have had a year to watch the airline woes with delays, and cancelations and the long lines and maybe thinking ‘you know I’ve only got five days to get away, I might as well just go by car.’”

Even car travel is expected to set a record, despite the national average price for a gallon of gas being around $5 — or even $6 in California.

The Associated Press contributed to this report.