There have been more than 2,700 flight cancellations since Christmas Eve as the recent COVID-19 surge has resulted in crew shortages and disrupted several airlines.
This comes on the day after Christmas, which is forecasted to be the third busiest air travel day for return flights.
More than 1,000 flights entering, leaving or inside the U.S. were canceled Sunday, and nearly 4,000 were delayed, according to flight-tracking website FlightAware.
As of 4:30 p.m. ET Sunday, 145 flights were canceled by Delta, 112 by JetBlue, 107 by United and 76 by American Airlines, according to FlightAware.
On Christmas Day, 997 flights were canceled and another 689 flights were canceled on Christmas Eve.
Delta and JetBlue have called on the U.S. Centers for Disease Control and Prevention to shorten the quarantine period for vaccinated individuals to five days, to ease the crew shortage.
Passengers are urged to check with their airlines and airports for up-to-date information on their flights.