Delta has already added over 100 people to its no-fly list for refusing to wear masks

• Delta's CEO recently revealed that the airline had banned over 100 people for refusing to wear a mask.
• Masks have been required on Delta flights since May 1.
• If a customer wants a medical exemption from wearing a mask, they must be cleared by a doctor from the University of Pittsburgh Medical Center, which is working with the airline.

Delta CEO Ed Bastian said on Wednesday morning that "over 100 people" have been added to a company-wide no-fly list after they refused to follow the airline's mask mandate.

"If you insist on not wearing your mask, we will insist that you don't fly Delta," said Bastian, during an appearance on "The Today Show."

Bastian urged those who want to fly without a mask to either travel via different means, or reconsider travel plans as a whole.

Masks have been required by the airline since May 1st, and the company has also halted the sale of middle seats in order to help slow the spread of coronavirus. A recent MIT study found that removing the middle seat decreased the chances of being infected by the coronavirus from 1 in 4,300 to 1 in 7,700.

If a traveler wants to fly without a mask, they must complete a "Clearance-T0-Fly" screening when they arrive at the airport. This process will be done in partnership with the University of Pittsburgh Medical Center.

The screening takes place over the phone, and the physician will decide if the customer can fly maskless or not. If they do not have a medical condition that allows them to fly without a mask, they can be rebooked on a later flight or get a refund from the airline. Making false medical claims can result in a suspension from the airline as well.

The airline has not said when the mask mandate will end.