More than 400 people have been banned from flying on Delta Air Lines because they didn't follow the airline's mask policy.
That's according to a memo to employees from CEO Ed Bastain, which states 460 people have been added to the airline's no-fly list.
"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," the memo says.
In August, 270 people were on Delta's no-fly list for refusing to wear a mask, CNN says.
Back in June, many major U.S. airlines said they'd be enforcing mask policies, with some saying they'd suspend people's flying privileges if they didn't comply, Airlines for America said.
The federal Centers for Disease Control and Prevention (CDC) recommends wearing a mask when traveling and at transportation hubs, like airports.
Requiring masks is one of several things Delta says it's doing to keep staff and travelers safe. Others include: blocking middle seats through at least Jan. 6, 2021; HEPA filters onboard planes; hand sanitizing stations; plexiglass shields at check-in counters; and social distancing markers.
Delta is the largest carrier from Minneapolis-St. Paul International Airport.