Delta’s mask policy is not a suggestion, it is mandatory.

Passengers refusing to follow the rule to keep face masks on at all times (except eating or drinking) don’t get to fly with Delta. It’s just that simple.

As of August 27, Delta CEO said that it has banned nearly 240 people from flying with the airline.

“Although rare, we continue to put passengers who refuse to follow the required face-covering rules on our no-fly list,” says Delta CEO Ed Bastian in an internal memo to employees shared with CNN.

The memo celebrates the opening of Delta’s new Salt Lake City hub and included references to the carrier’s current state of affairs, its continued growth, and the considerable impact that coronavirus has had on managing the health and safety of staff and passengers.

“Systemwide, we continue to identify opportunities to speed up our airport projects and position Delta to lead in the recovery with world-class facilities that will help us transform the customer experience,” Bastian said in the memo.

From mandatory mask rules to keeping middle seats vacant and the reduction of food and drink service, struggling airlines are doing what they can to curb the spread of the virus while trying to stay in business.

Since the policy has been implemented in June, the number of Delta passengers on the no-fly list has more than doubled in less than a month. 

“We’ve had well over 100 people that have refused to keep their mask on during the flight,” Bastian said in a CNN report on August 7.

The federal government has not implemented mask-wearing regulations, unlike the enforceable requirements around wearing seatbelts and not smoking on planes. This leaves it up to airlines to police passenger behavior, which has resulted in strict new policies.

Passengers who will not abide by the mask-wearing rules will face consequences like being banned from future flights.

“As we all work toward the recovery, it’s vital that we continue to stay focused on the drive to provide the safest, cleanest airports, aircraft, and workspaces possible,” Bastian said in the employee memo.

Delta requires passengers to wear masks starting at check-in. Last month, the Atlanta-based airline began telling passengers who cannot wear a mask because of a health condition to consider staying home.