Glimmers of a gradual return to air travel mean airlines are rolling out new policies aimed at protecting passengers and crew from coronavirus transmission and increasing consumer confidence in air travel safety.
Multiple airlines are announcing that passengers will soon be required to wear face masks.
JetBlue Airways announced that it will require all passengers to wear face masks starting on May 4. Crew members were already required to wear masks.
JetBlue's move follows American Airlines' announcement on Monday that flight attendants will be required to wear masks beginning on May 1.
American will also start handing out sanitizing wipes and gels and face masks to customers in early May, "as supplies and operational conditions allow," the news release said.
As people in many corners of the world begin to move around more freely, airlines are issuing policies that are likely to evolve with the pandemic.
All of the carriers have plans for enhanced cleaning and sanitation.
Video: Air travel down, but some report crowding on board
Here's where some major carriers stand so far on personal protective equipment and social distancing measures:
All United Airlines flight attendants are required to wear face masks. United was the first major U.S. carrier to announce the requirement.
United Airlines will begin to provide masks to passengers in early May, a company spokesperson told CNN.
"We are not mandating that passengers wear a mask, however, we strongly encourage travelers follow CDC guidance to wear a face covering when social distancing is difficult," said Nicole Carriere, a spokeswoman for United. "By providing the masks, we're making it that much easier for them to do so."
The carrier has also modified in-flight service to minimize touchpoints and has moved primarily to pre-packaged foods and sealed beverages.
United is also implementing changes to boarding and seat assignments to promote social distancing through at least May 31.
Delta Air Lines
Delta Air Lines will require customers to wear face masks starting May 4.
Delta is also blocking middle seats and reducing the number of passengers on each flight, boarding customers 10 at a time and changing food and beverage service to reduce touchpoints between passengers and crew, according to measures outlined on the carrier's website.
The airline is requiring all employees to wear masks or face coverings when unable to maintain the six-foot social distancing rule, the airline said in a memo to employees on Monday.
American Airlines will require customers to wear face masks or coverings starting May 11.
In addition to handing out masks to passengers and requiring flight attendants to wear them starting in May, American Airlines has turned off some computers and kiosks at ticket counters to her encourage social distancing.
Signage at gates reminds passengers not to crowd together during the boarding process. American has also reduced food and beverage service through April 30 and has limited the number of passengers on each aircraft through May 31.
"American will not assign 50% of main cabin middle seats or seats near flight attendant jump seats on every flight, and will only use those middle seats when necessary," the carrier's temporary policy reads.
JetBlue is the first major U.S. carrier to require that passengers wear masks, effective May 4.
"Wearing a face covering isn't about protecting yourself, it's about protecting those around you," said Joanna Geraghty, president and chief operating officer of JetBlue, in a statement. "This is the new flying etiquette."
JetBlue has also limited the number of available seats on most flights and regularly reviews seat assignments to maximize space between passengers.
The carrier has adjusted food and beverage service to minimize touchpoints, with more limited offerings in many fare classes.
Southwest Airlines will begin requiring customers to wear wear masks aboard its planes starting May 11.
“It is highly encouraged to bring your own hand sanitizer and mask, and to wear your mask while traveling. Face coverings or masks will be required for Customers starting May 11. If you forget your mask at home, one will be available for you," the company said in an update to travelers.
Frontier Airlines, a smaller, Denver-based carrier, announced that passengers would be required to wear a face covering over their nose and mouth at the airline's ticket counters, gate areas and onboard starting May 8.
The airline is blocking every other row and requires passengers to agree to a "health acknowledgment" before checking in, to certify that they have not been exposed to COVID-19, do not have a temperature and promise to wash their hands before boarding.
All Air Canada passengers are required to comply with a Canadian government mandate that all passengers flying through, to or from Canada wear a non-medical face mask or face covering over their nose and mouth.
Air Canada has adjusted its boarding procedures and is reseating customers to enable social distancing. Where adequate spacing isn't possible, passengers can choose to take a later flight at no additional cost.
Services and amenities have also been adjusted to mitigate the risk of viral transmission. Some food service has been suspended or shifted to pre-packaged fare and bar service and pillows and blankets are no longer available on some flights.
Masks and other protective equipment common in Asia
Since April 23, Malaysia Airlines has required all passengers (excluding infants) to wear face masks.
Korean Air is providing cabin crew with protective clothing, including goggles, masks and gloves.
"Protective gowns are being provided on medium- and long-haul inbound flights as overseas COVID-19 cases continue to increase significantly," Korean Air says in outlining its protective policies.
All Korean Air passengers are required to wear masks, and the airline is providing surgical masks and hand sanitizer at airports and on aircraft.
Some European carriers are offering or requiring masks
Passengers must wear face masks when flying with Lufthansa Group beginning May 4. The group includes Lufthansa, Swiss and Austrian Airlines. Flight attendants will also be required to wear masks, according to a Lufthansa Group news release.
Lufthansa added that leaving middle seats vacant will no longer be necessary.
"As a result of this new regulation, the middle seat that has thus far been left vacant in Economy and Premium Economy Class, will no longer remain a necessity, as the facial covering provides the necessary protection," the news release said.
"Yet, currently, due to a decrease in flight demand, seats will be allocated as far apart as possible throughout the cabin."
Air France says on its website that the majority of its flights are not full, allowing social distancing.
"In cases where social distancing is not possible, our crews distribute masks at the aircraft door to customers who do not already have them," the site says.
Dutch carrier KLM says its crew members wear "mouth caps and protective gloves." CNN has asked for clarification and information on whether passengers are required to wear masks.
Hearst TV contributed to this report.