Delta Air Lines banned 460 anti-mask flyers who violated the mandated policy.
That number was just under 300 people in August.
All major airlines have mandated face coverings as the industry struggled to regain revenue on par with pre-pandemic numbers.
In June, Delta and other airlines revealed passengers who don't comply could be banned from future flights.
Delta Air Lines required all passengers who cannot wear a face mask due to health concerns to undergo a medical screening in July.
Footage of airline confrontations over face masks have erupted online.
More than 400 travelers won't be flying with Delta Air Lines anymore after they were banned for flouting its strict face mask policy, according to a memo.
In just five months, the no-fly list for 'The World’s Most Trusted Airline' has jumped by hundreds as wary travelers slowly return to the skies.
'As of this week, we've added 460 people to our no-fly list for refusing to comply with our mask requirement,' Delta CEO Ed Bastian told employees, CNN reports.
It comes after Delta implemented its face covering mandate on May 4, when just over 1.1million Americans were infected and 68,000 had died. As of Sunday, that number has skyrocketed to 8.7million cases and a death toll of 224,900.
All major airlines have implemented face mask mandates, but a federal one was never ordered by the Trump administration.
In August, Delta Airlines revealed that it prohibited around 270 passengers since the pandemic began.
'You can't get on the plane without wearing your mask. But we do have some customers that don't want to keep their mask on during flight,' Bastian told CNN Business at the time.
'We remind them several times over the course of getting ready to take off to please keep that mask on. But if they insist upon not wearing it — we insist that they're not going to travel on Delta today.'
But airlines have not shared their 'no-fly' lists with each other, meaning it's possible for a passenger to be barred from Spirit Airlines and still book flights with United Airlines.
The airline industry was dealt a crushing blow in March as lockdown restrictions were instituted and would-be passengers avoided unnecessary travel.
Delta Air Lines, founded in Macon, Georgia, in 1925, started off the new year strong in January at $62.03 per share on January 17. That price plunged to a low of $19.38 on May 14.
Since then, Delta has managed to regain some traction as Americans gradually fly more, but it's well below what the company typically saw.
Cell phone footage of face mask confrontations on airplanes have become commonplace on social media.
Recently, an unidentified passenger caused a commotion when she refused to properly wear a face covering and punched a flight attendant.