RELATED: Never Do This When Your Flight Is Canceled, Travel Expert Warns. A surge of recent flight cancellations has stretched from Christmas Eve into the new week. Globally, airlines canceled more than 6,000 flights on Christmas Eve, Christmas, and the day after Christmas, according to CNN. The news outlet said that more than 1,200 U.S. flights were canceled on Dec. 26.ae0fcc31ae342fd3a1346ebb1f342fcb And according to Bloomberg, about 1,160 U.S. flights were canceled just as of midday on Dec. 27, while more than 2,800 nationwide flights had been canceled over the weekend. Furthermore, 1,065 flights within, into, or out of the U.S. had already been canceled by midday on Dec. 28, per data from Flight Aware. While flight cancellations are affecting pretty every major U.S. airline at the moment, one stands above the rest. Data from FlightAware shows that Alaska Airlines had to cancel 144 flights on Dec. 27 and 103 so far on Dec. 28, which accounts for 21 and 28 percent of its total schedule, respectively. This has made it the hardest hit airline, according to Bloomberg. The news outlet reported that Seattle-Tacoma International Airport, the airport hub for Alaska Air Group, Inc. which operates Alaska Airlines, has been heavily affected by snowfall and some of the region’s coldest temperatures in years. And while Alaska Airlines had previously said it was struggling with crew members calling out sick for COVID, it said this was not a factor in its most recent flight cancellations, per Newsweek. “Snow and wintry conditions are creating a bit of a bah-humbug for our operations to and from Seattle. To adjust for the difficult weather conditions and impacts at Seattle-Tacoma International Airport, we’ve had to cancel some of our flights,” a spokesperson for the airline told Fox Business. “We apologize for any potential flight delays and cancellations that could take place due to the weather.  We realize it’s incredibly frustrating when travel doesn’t go as planned.” RELATED: For more travel news delivered straight to your inbox, sign up for our daily newsletter. While Alaska Airlines has been hit the hardest, it’s certainly not alone. On Dec. 27, American Airlines had to scrap 3 percent of its flights, while Delta expected to have around 200 mainline and regional flights canceled, according to Bloomberg. But in contrast to Alaska, many of these airlines have pointed to COVID as one of the main factors in recent flight cancellations. United Airlines said about 2.9 percent of its scheduled flights were canceled on Dec. 27 due to Omicron-related staffing issues. “Despite our best efforts, we’ve had to cancel a number of flights, and additional flight cancellations and other delays remain a possibility as we see more Omicron community spread,” a spokesperson for JetBlue told Fox Business. “The health and safety of our crewmembers and customers remains our top priority as we work through this pandemic, and we sincerely apologize for the inconvenience that these schedule changes bring during the holidays.” With the Omicron variant surging across the U.S., it might feel as if COVID-related flight cancellations are unlikely to improve. But some flight experts say new guidance from the Centers for Disease Control and Prevention (CDC) could help soon. Major U.S. airline CEOs recently urged the agency to shorten the isolation period for fully vaccinated individuals who contract asymptomatic cases of COVID so that they could reduce the number of crew members unable to work. “Swift and safe adjustments by the CDC would alleviate at least some of the staffing pressures and set up airlines to help millions of travelers returning from their holidays,” Derek Dombrowski, a JetBlue spokesman, told The New York Times. And on Dec. 27, the CDC did just that. The agency has now reduced its recommendation on the isolation period of people with asymptomatic COVID breakthrough infections from 10 days to five days. “The new CDC guidelines should be helpful to airlines and travelers,” aviation expert Henry Harteveldt told ABC News. “The shorter isolation time will allow asymptomatic employees to return to work sooner, increasing the number of crew members available to work, and reducing the risk that flights will have to be canceled.” Delta Air Lines, which was one of the first in the U.S. to ask the CDC to revise their isolation guidelines, told ABC News that it is already working to implement the new guidance. “The updated guidance allows more flexibility for Delta to schedule crews and employees to support a busy holiday travel season and a sustained return to travel by customers,” the airline said in a statement. RELATED: Delta Air Lines Is Cutting These Flights for the Next Two Months.