More than 1,700 flights canceled in the US Wednesday, almost 20,000 since Christmas Eve

More than 1,700 U.S. flights were canceled on Wednesday, bringing the total number of flight cancellations since Christmas Eve to nearly 20,000.

A total of 1,760 flights within, into or out of the U.S. were canceled as of 9:15 p.m. EST on Wednesday, according to FlightAware. Airlines also reported more than 4,800 delays for U.S. flights.

Southwest canceled 531 flights on Wednesday, and United called off 169 trips.

Airlines for weeks have been forced to cancel flights because of staff shortages driven by the surge in COVID-19 cases nationwide and inclement weather across the country.

The spike in cancellations coincided with this year’s holiday season, a busy time for airline travel. According to The Washington Post, nearly 20,000 U.S. flights have been canceled since Christmas Eve.

Passengers, however, are still traveling despite the large number of cancellations. The Transportation Security Administration said more than 1.66 million individuals traveled through checkpoints on Tuesday, the same day more than 1,500 flights were canceled.

The swelling number of flight cancellations, however, may start to subdue after the Centers for Disease Control and Prevention shortened its isolation guidance for asymptomatic individuals, lowering the length of time from 10 days to five days. For the subsequent five days, however, it is recommended that individuals wear masks.

People who test positive for the virus on the fifth day of isolation should continue to isolate for five more days.

The guidance change came days after Delta CEO Ed Bastian asked the health agency to shorten its quarantine instructions for breakthrough cases.