(CNN) — US airline passengers who figured face mask enforcements had more bark than bite could end up getting bit.
The announcement comes in lieu of a federal regulation requiring all passengers to wear masks -- the sort of enforceable measure that governs requirements to wear seatbelts and not smoke.
Delta Air Lines and United Airlines have come out with specific statements warning passengers of the consequences of not wearing a face covering during flights.
What Delta is doing
Want to stay in Delta's good graces for future flights? The airline says you'll have to follow the rules on wearing masks during flights.
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On Tuesday, Delta issued a statement emphasizing the importance of face masks in its efforts to stop the spread of Covid-19.
Delta said passengers must be wearing a mask to board and must keep it it on during the flight.
What happens if you get on board and ditch the mask?
"Those who choose not to comply with this or other safety requirements risk future flight privileges with Delta, which is in keeping with the face covering enforcement policies Airlines for America recently announced," Delta said. It did not lay out how that process will work in the statement.
Delta noted that wearing a seatbelt during takeoff is also a requirement, and that is it taking its mask requirements just as seriously.
The airline said it will send digital notifications to its passengers before flights and will provide reminders during passage.
What United is doing
United Airlines came out Monday with its own separate announcement that has more teeth than what it's been doing so far. If you refuse to wear a face mask starting June 18, you could find yourself on a restricted travel list.
Here's how United laid out the process for at least the next 60 days for people who eschew a mask:
First, flight attendants will inform you of the mandatory mask requirements if you're not wearing a face covering, and you do not fall within a small group of exceptions.
If you don't have a face covering, United flight attendants will offer you one.
Bring your own face mask from home or United will supply you with one for your flight.
If some fliers still refuse to wear a mask, the attendants "will do their best to de-escalate the situation [and] again inform the customer of United's policy."
United's policy does not include forcibly removing a passenger who still refuses to comply, but the attendants will file an incident report.
The airline says that "any final decision or actions regarding a customer's future flight benefits will not occur onboard but instead take place after the flight has reached its destination, and the security team has investigated the incident."
Each carrier will have its own rules
Six other major US airlines -- including American Airlines and Southwest Airlines -- pledged to roll out new policies requiring masks, also enforced with a penalty as severe as a ban on flying with that particular airline.
"Each carrier will determine the appropriate consequences for passengers who are found to be in noncompliance of the airline's face covering policy up to and including suspension of flying privileges on that airline," said Airlines for America.
The lack of federal action has driven the airlines to act, according to a source familiar with the discussions.
Other airlines are expected to lay out specific policies as well as enforcement procedures for crew members to follow in the coming days, the source said.
Federal government: It's up to the airlines
Transportation Secretary Elaine Chao said she opposed direct federal rules on face masks during flights.
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A spokesperson for the Department of Transportation weighed in on the federal government's position on requiring passengers to wear face masks in flight. "As we move through the phases of reopening, the FAA will continue to support airlines and their frontline employees as they implement these CDC guidelines to ensure the health of the traveling public."
Transportation Secretary Elaine Chao had opposed a federal requirement on masks. She said the issue was best determined by airlines and unionized frontline workers, who are most at risk if coronavirus spreads on planes.
"When the federal government gets involved, we tend to be much more heavy handed, we tend to be inflexible, and once we put a rule in place, it takes a long time to remove that rule if conditions change," Chao said at a June 3 event hosted by Politico.
But a major union representing flight attendants said last week the current approach was not working.
Association of Flight Attendants official Susannah Carr, who is also a flight attendant with United Airlines, testified before the House Transportation Committee that her colleagues have discussed "the fact that passengers don't like to wear the mask, might take it off for a longer period than just to eat or drink."
"It's definitely an issue that we need to address," she said.
Responding to the action by Airlines for America, Sara Nelson, who is the President of the Association of Flight Attendants said in a statement: "Masks are essential to keep passengers, flight attendants, and frontline aviation workers safe during the Coronavirus pandemic. It is also essential to rebuild confidence in air travel.
"The federal government has completely abdicated its responsibility to keep the flying public and aviation workers safe during Covid-19," the statement continues.
"[This] action by Airlines for America members is important, but the industry alone cannot fix this. We once again call on the federal government to mandate masks for passengers and frontline workers and implement broader action on Covid-19 safety measures in aviation."
Some fliers upset, too
Passengers board an American Airlines flight to Charlotte, North Carolina, at San Diego International Airport on May 20. Tensions can rise between passengers who wear a face mask and those who don't.
Sandy Huffaker/Getty Images
Flight attendants weren't the only people upset about some people not wearing masks. Passengers who are cooperating with mask requirements have been livid with their non-masking-wearing seatmates.
Take Tony Scott's experience. A 53-year-old African American man with lung issues, he told the New York Post about his frustrating flight with American Airlines in May.
He decided after 55 days in self-quarantine in California to fly to Texas and stay with his son.
Scott told the Post that airline's mask-wearing mandate for passengers was what made him feel comfortable flying at all. But when he got on the flight, he found his seatmate unmasked.
He offered to move out of his first-class seat, but the request was denied.
Scott said he felt like the airline didn't take his concerns about the seatmate, a white woman he figured to be in her late teens and who wouldn't put a mask on, seriously.
Policies without teeth
Policies requiring masks -- first for crew, and then for passengers -- were rolled out by the major airlines in April and May, but with no federal regulation, flight attendants have been instructed to request compliance through de-escalation techniques.
Airlines for America said the forthcoming changes include announcements on flights outlining "specific details regarding the carrier's face covering policy including the consequences passengers could face for violating the policy."
Some airlines, the group said, will require passengers to agree to mask compliance during check in. United Airlines began doing that last week.
It said customers who "are not able to confirm these requirements," including that they have not been have not had symptoms or been around anyone who has Covid-19 in recent weeks, will not be permitted to check in.