Alaska Airlines is now requiring its 22,000 employees to receive the COVID-19 vaccine under new federal rules as early as Dec. 8. The airline had previously offered its employees a $200 bonus to provide proof of full vaccination, CNBC reports.

The airline had since extended the incentive to last from Oct. 15 to Dec. 1.

The Seattle-based company released a statement on Thursday, saying, “Since our company does significant work for the federal government, we have determined that Alaska Airlines, Horizon Air, and McGee employees – all part of Alaska Air Group – do fall under this federal vaccine mandate, along with other major U.S. airlines.”

“This means all of our employees, including certain contractors and vendors, will be required to be fully vaccinated, or be approved for a reasonable accommodation such as medical conditions or religious beliefs that prevent them from being vaccinated,” the airline added.

An airline spokesperson told CNBC that a “significant” portion of their employees are already vaccinated against the virus but did got give a percentage.

Alaska Airlines is not the only airline to mandate their employees get vaccinated as U.S. United Airlines employees could face termination if they fail to comply. As of last week, more than 96% of United’s 67,000 employees had been vaccinated, with about 2,000 seeking exemptions for medical or religious reasons, and 593 facing termination.

“This was an incredibly difficult decision but keeping our team safe has always been our first priority,” United Airlines CEO Scott Kirby said. Kirby has also urged other companies to mandate the vaccine for their employees.