In an internal memo obtained by CBS News, Delta Air Lines CEO Ed Bastian informed his employees Thursday that 270 passengers have been added to their no-fly list over their refusal to abide by the company's policy which requires everyone wear a face covering during flights. 

"The use of face masks remains a top priority for reducing the spread of the virus. That's why masks are required for employees and our customers," Bastian said. "To date, we've added 270 passengers to our no-fly list for refusing to comply with that requirement on our planes."

Delta required passengers to undergo a medical screening by phone prior to boarding the aircraft, if they wanted to be exempt from wearing a face covering. The company said that anyone who provided false medical excuses to get around their mask policy could be banned from future flights.  

While other airlines started to scale back their efforts to curtail the spread of COVID-19 as early as July, Delta has exercised other methods to ensure the safety of their passengers, including preventing the sale of the middle seat until, at least, the end of the month. These practices have come at a cost for Delta's bottom line, which is why the airline is looking elsewhere to reinvigorate travel in wake of the pandemic.

Delta announced Monday that the company is eliminating change fees on all flights within the U.S., Puerto Rico and the U.S. Virgin Islands, effective immediately. United and American Airlines have done the same.