By Kelly Yamanouchi, The Atlanta Journal-Constitution

The omicron variant of COVID-19 is contributing to cancellations of some flights scheduled for Christmas Eve.

Atlanta-based Delta Air Lines said late Thursday it has canceled 90 flights scheduled for Friday due to a combination of issues, including the impact of the omicron variant and the potential for bad weather. By morning, the total had risen to 135 flight cancellations for Friday.

Delta said it had “exhausted all options and resources — including rerouting and substitutions of aircraft and crew to cover scheduled flying” before moving forward on the flight cancellations, which make up less than 5% of its flight schedule. “We apologize to our customers for the delay in their holiday travel plans,” Delta said in a statement. The airline advised customers to check Delta’s website or app for flight updates.

United Airlines said late Thursday it canceled about 120 flights scheduled for Friday. “The nationwide spike in omicron cases has had a direct impact on our flight crews and the people who run our operation. As a result, we’ve unfortunately had to cancel some flights,” Chicago-based United said in a statement, adding that it is working to rebook as many people as possible “and get them on their way for the holidays.”

In addition to the impact of COVID-19 on flight crews, Delta also anticipates storms through its hubs in Seattle and Salt Lake City in coming days, and issued waivers allowing flight changes without additional costs for flights to, from or through those cities.

The flight cancellations come after Delta CEO Ed Bastian earlier this week raised concerns about the impact of the variant on the airline’s workforce and operations, saying the surge “may exacerbate shortages and create significant disruptions.” In a letter to Rochelle Walensky, director of the Centers for Disease Control and Prevention, Bastian asked the CDC to reconsider a guideline for 10 days of isolation for COVID-19 infections in vaccinated people, and proposed a shorter isolation period.