No mask? On Delta, you'll now need a note from the airline's doctor

In order to get people back in the sky, Delta needs to reassure customers that it's safe.

And of the U.S. airlines, Delta's doing a great job towards that goal. It's capping the capacity of all its flights, cleaning planes at each turn and modifying inflight service protocols.

Additionally, the Atlanta-based airline requires passengers to wear masks or appropriate face coverings throughout the end-to-end travel journey.

While ground agents and flight attendants can police mask-wearing, it's hard to enforce compliance. As we've seen with the explosive growth of emotional support animals, it's hard for an airline to judge what's legitimate and what's not.

Yet, passengers need to be assured that everyone else on the plane wears a mask to ensure their safety. After all, coronavirus cases are rising steadily across most of the country.

Related: We got an inside look at how Delta is cleaning planes between every flight

Nonetheless, there are some passengers with legitimate medical reasons as to why they can't wear a mask. It's likely far and few between, but some exceptions exist.

Enter the doctor.

Starting Monday, July 20, Delta will require any passenger who refuses to wear a mask to speak virtually with a medical professional before the flight, the airline told TPG in an exclusive interview on Friday after we inquired about updates to the mask policy.

In addition, as of July 29, Delta will require all passengers to complete a health acknowledgment form before check-in that includes a question about whether you're going to wear a mask throughout the end-to-end travel journey.

According to a Delta spokesperson,

Medical research tells us that wearing a mask is one of the most effective ways to reduce the COVID-19 infection rate. That’s why Delta remains committed to requiring customers and employees to wear a mask or face covering as a consistent layer of protection across all Delta touchpoints. We encourage customers who are prevented from wearing a mask due to a health condition to reconsider travel. If they decide to travel, they will be welcome to fly upon completing a virtual consultation prior to departure at the airport to ensure everyone’s safety, because nothing is more important.

Delta is doubling down on its mask requirement. If a customer cannot wear a mask, the airline would prefer that they reconsider travel — quite the statement for an airline. But flying can be essential, and this new process is trying to make it as safe as possible.

If you pass the "Clearance-to-Fly" screening, then you'll be allowed to board the plane without a mask. If you fail, however, your flight will be rebooked for a later date, or you'll be offered a refund (even if you've got a nonrefundable ticket).

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The consultation is a private phone call with the dedicated medical personnel facilitated by Delta ground staff. It will be conducted out of earshot from others. Pending the outcome of the consultation, final determination to fly is made.

All customers who need a mask exemption should arrive at the airport at least an hour earlier than normal. If you don't, you'll risk missing your flight. You won't be able to board until you've received medical clearance.

If you misrepresent a disability or health condition, your level of welcome on future Delta flights will be jeopardized. After all, such a passenger could be an asymptomatic carrier of the coronavirus. Without a mask on, that person could spread the virus inflight, which would likely turn into a much larger issue for the airline.

Likewise, if you board with a mask on and take it off inflight while not eating or drinking, your flying privileges may also be suspended.

Related: Delta will ban flyers who do not wear masks

These medical consultations are available 24/7 globally, so you don't need to worry about missing your red-eye international flight due to the office being closed.

Like it does with other inflight medical emergencies, Delta's leveraging its STAT-MD partnership to handle the pre-flight consultation. Based at the University of Pittsburgh Medical Center, STAT-MD medical personnel support both inflight emergency consultations, as well as fitness to fly ground-based screenings.

All in all, Delta's latest move will help the carrier enforce its mask-wearing policy. Time will tell whether other U.S. carriers take the cue and implement similar procedures.