At least 730 flights canceled across US on Sunday

At least 730 flights were canceled across the United States on Sunday, according to the flight-tracking website FlightAware.

Delta Air Lines alone canceled at least 224 flights on Sunday. United Airlines canceled 71 flights and American Airlines canceled 66 flights.

CNN has reached out to the three airlines for comment on flight cancellations.

"Delta teams continue to safely manage through compounding factors affecting our operation this weekend, including higher-than-planned unscheduled absences in some of our work groups, weather, and air traffic control constraints," a Delta Air Lines spokesperson said. "Canceling a flight is always our last resort, and we sincerely apologize to our customers for any disruption to their travel plans."

Atlanta's Hartsfield-Jackson International Airport was most impacted by Sunday's cancellations.

United Airlines canceled 56 flights on Saturday and 70 flights Sunday.

United Airlines said on Thursday it would cut 12% of its daily domestic flights from its busy Newark hub. The cuts start in July and amount to about 50 daily flights.

According to FlightAware, there were 634 flight cancellations Saturday.