Holiday travelers continued to experience widespread flight cancellations as the omicron variant causes airline staff to call in sick.
According to FlightAware, which tracks delays and cancellations, there have been 2,395 total flight cancellations around the world Monday with 869 of those impacting flights “within, into, or out of the United States.”
Some 6,342 flights have been delayed around the world with 1,602 delays impacting U.S flights.
Over the Christmas weekend, thousands more flights were canceled, leaving travelers stranded.
"We apologize to our customers for the delay in their holiday travel plans," Delta said in a statement. "Delta people are working hard to get them to where they need to be as quickly and as safely as possible on the next available flight."
The holiday season is the busiest time of year for air travel. The U.S. Transportation Security Administration said 2.19 million passengers were screened on Dec. 23, and the previous day saw more travelers than the same day in 2019.
When things might return to normal is unclear.
Delta and JetBlue have reportedly asked the U.S. Centers for Disease Control and Prevention to reduce quarantine times for their vaccinated employees. Some airlines are also reportedly offering bonuses to work more to cover for sick employees.
Amid the scramble, some are expressing concern.
“We've got to make sure employees don't feel pressured to come to work when they've been exposed to COVID or they think they may have the symptoms," Captain Dennis Tajer, a spokesperson for the Allied Pilots Association, told ABC News.