Delta says passengers who don’t wear masks face a health screening.

Delta Air Lines said it would require passengers unable to wear face masks because of health conditions to undergo a medical clearance at the airport before boarding — or the passengers should “reconsider travel” altogether.

The policy is an addition to Delta’s rules that call on passengers to wear face masks at check-in, boarding gates and during the flight. It follows reports of some passengers on U.S. airlines failing to wear masks onboard and air staff not enforcing them.

“Customers with health conditions or disabilities that explicitly prevent the wearing of a face covering or mask are strongly encouraged to reconsider travel or should be prepared to complete a ‘Clearance-to-Fly’ process,” the statement said.

The screening process will take place before departure at the airport and can exceed an hour, the airline said. Should passengers falsify health claims, the statement said, they risk being barred from the airline until masks are no longer required.

Delta in July is running only 30 percent of its normal flight schedule.

The carrier’s pilots union said that 2,235 of Delta’s 14,000 pilots volunteered for early retirement during a sign-up period that ended Sunday night. It was not immediately clear how that would affect the nearly 2,600 pilots who were warned of a possible furlough weeks ago.

On Friday, the airline told its pilots that it could avoid a furlough for a year if they agreed to a 15 percent cut to guaranteed pay, a move that the union criticized as circumventing official negotiations.