To ensure passengers are safe from the coronavirus when flying, the majority of airlines have implemented a face mask policy across their operations. But with this policy comes some consequences for those who choose not to obey it, resulting in hundreds of passengers being banned from flying.

Delta (DAL) CEO Ed Bastian said in an internal memo to employees, obtained by ABC News, that as many as 460 passengers have been added to the airline's no-fly list for violating the company’s face mask policy.

Delta announced back in July that it would ban any passenger who did not comply with its face mask requirement for the duration of the policy. Delta’s face mask policy extends to airports, check-in, in-flight, deplaning, and at baggage claim, regardless of the airport it serves.

"Wearing a mask is among the simplest and most effective actions we can take to reduce transmission, which is why Delta has long required them for our customers and our people," Bastian wrote in the memo. "As of this week, we’ve added 460 people to our no-fly list for refusing to comply with our mask requirement."

Delta is not the only airline that put passengers on its no-fly list for failing to follow its face mask policy. According to several news reports, American Airlines, United Airlines, Spirit, Frontier Airlines, Alaska Airlines, and Hawaiian Airlines also have banned passengers for violating their face mask policies.

United had banned 150 passengers from flying with the airline as of September, along with Spirit (128 banned), Frontier, (106), Alaska Airlines (78), and Hawaiian Airlines (six), the Los Angeles Times reported.

Several airlines have had videos of irate passengers go viral after being removed from their airplanes for failing to comply with multiple requests to wear a face mask in-flight.

There are over 43 million positive cases of the coronavirus in the world, with more than 1.1 million COVID-19-related deaths, according to data from Johns Hopkins University.

Shares of Delta were trading at $32.49 as of 10:55 a.m. EDT, down $1.51 or 4.43%.

Passengers wear face masks after their flight arrived at Heathrow Airport in London Passengers wear face masks after their flight arrived at Heathrow Airport in London Photo: AFP / DANIEL LEAL-OLIVAS