RELATED: American Is Cutting Flights From These 6 Major Cities, Starting in February. As with every other airline, United Airlines has had to cancel a staggering number of flights since Christmas weekend as the Omicron variant continues to circulate. In a memo to employees, United CEO Scott Kirby gave insight into just how worrying the company’s situation is right now. According to Kirby, the airline has about 3,000 workers who are currently out of work because they are positive for COVID, CNBC reported. That is close to 4 percent of United’s entire U.S. workforce. RELATED: Alaska Airlines Is Getting Rid of This on Flights, Effective Immediately. While staff shortages are spread throughout the country, some airports are getting hit extremely hard. “Just as an example, in one day alone at Newark [New Jersey], nearly one-third of our workforce called out sick,” Kirby said in the memo. Newark Liberty International Airport is one of United’s eight hubs, servicing hundreds of flights from the airline every day. “Our frontline teams continue to put in a tremendous effort during what I know is an incredibly challenging and stressful time—the Omicron surge has put a strain on our operation, resulting in customer disruptions during a busy holiday season,” Kirby said, per The New York Times. On Jan. 11, United had to cancel 154 of its flights, which accounted for 7 percent of its daily schedule, according to Flight Aware, a real-time flight tracking website. In a memo posted to the company’s website that same day, Kirby indicated that these cancellations were inevitable, despite United working to minimize damage. “While we go to great lengths to avoid cancelling flights, we worked to get ahead of the impact by acting early to cancel flights when necessary and notifying impacted customers in advance of them coming to the airport,” he said. In order to help United continue to be able to “get a high percentage of [its] customers on other flights and close to their original arrival time,” the airline will be cutting even more flights in the near future to mitigate troubles from staffing shortages. “We’re also reducing our near-term schedules to make sure we have the staffing and resources to take care of customers,” Kirby said. RELATED: For more travel news delivered straight to your inbox, sign up for our daily newsletter. In August, United Airlines became the first major U.S. airline to require that employees get vaccinated against COVID or face termination. To date, United has one of the strictest requirements of any airline. In October, Kirby confirmed that the company was currently in the process of terminating a total of 232 U.S. employees who were still unvaccinated. Six of these workers were pilots for United, according to Business Insider.ae0fcc31ae342fd3a1346ebb1f342fcb More than 96 percent of United’s staff is vaccinated as of Jan. 2022, Kirby confirmed to CNBC. The CEO said it’s important to note that none of the airline’s 3,000 COVID-positive employees who are also vaccinated are hospitalized. Prior to United’s vaccine requirement, more than one airline employee had died from COVID on average per week, but the airline has now gone eight consecutive weeks without a COVID-related death among its vaccinated employees. “In dealing with COVID, zero is the word that matters—zero deaths and zero hospitalizations for vaccinated employees. And while I know that some people still disagree with our policy, United is proving that requiring the vaccine is the right thing to do because it saves lives,” Kirby said in his Jan. 11 memo. RELATED: This One Thing Is Being Banned at 50 U.S. Airports, Starting Jan. 19.