As coronavirus restrictions begin easing in parts of the U.S., several airlines have introduced precautionary measures, such as mandatory face coverings and spaced seating, as flights resume operations from later this month.

Denver-based Frontier Airlines is offering a "More Room" seat option, which costs from "$39 per passenger, per flight," allowing passengers to reserve an empty seat next to them, the airline announced in a statement on Monday, while other carriers are temporarily banning the sale of middle seats on planes.

"Flights departing May 8 through August 31, 2020 will have 18 More Room seats available for passengers to select, including Stretch seats in the first three rows of the aircraft, which also provide extra legroom and recline as compared to standard seats. Frontier will announce at a later date whether the More Room program will be extended beyond August 31," Frontier said in the statement.

Starting from May 8, Frontier will also require passengers to wear a face covering over their nose and mouth at airline ticket counters, gate areas and aboard the aircraft. Face coverings have been required for flight crew since April 13, the company notes.

Also from April, the airline has required passengers to receive a "health acknowledgement" before completing check-in at the company's website or on its mobile app.

Passengers are required to certify that "Neither they nor anyone in their household has exhibited COVID-19 related symptoms in the last 14 days, they will check their temperature before heading to the airport and not travel if they have a fever, they will wash their hands/sanitize before boarding the flight," the airline said in its statement.

Last month, Delta and Alaska Airlines announced they will temporarily stop selling middle seats as part of their precautionary measures amid the pandemic.

Through June 30, Delta is "blocking middle seats in Main Cabin, Delta Comfort+ and Delta Premium Select across all flights. When booking your future seat selection via the Fly Delta App or online, middle seats will be shown as unavailable," Delta announced in a statement last month. Customers will also be boarded at a maximum of 10 people at a time.

Alaska Airlines has capped first class seat sales at 50 percent, while all middle seats on large aircraft and all aisle seats on small aircraft will not be available for purchase through May 31.

"We may need to ask you to change a previously assigned seat to provide for additional distancing," Alaska Airlines notes on its website.

"Extra space between guests is not guaranteed and is subject to weight and balance restrictions through 5/31/20. We'll re-evaluate our efforts to provide extra space in mid-May. Families or large groups wanting to sit together can make the request with reservations or at the airport," the airline confirms.

American Airlines is also blocking off 50 percent of its middle seats, while JetBlue is allocating only around a third of its seats.

"We are capping our flights whenever possible to allow for a level of social distancing, relaxing our assigned seating policy and proactively assigning seats to maintain distance among customers not traveling together," a JetBlue spokesman told USA Today last month.

Several other U.S. carriers, including American Airlines and United, have also recently announced measures either requiring or encouraging passengers to wear face masks aboard their flights.

"The use of face covering inflight is among the measures proposed in an industry roadmap for the restart of flights that we are discussing with industry stakeholders and governments," a spokesperson for the International Air Transport Association (IATA) told the BBC.

An almost empty British Airways plane from Milan to London, pictured on March 5, 2020 in Milan, Italy.Getty Images

Many airlines across the globe, including in the U.S., Latin America, Europe and Australia, have canceled nearly 90 percent of their international flights following the COVID-19 virus outbreak.

On Sunday, the Transport Security Administration (TSA) reported seeing only 6.8 percent of the number of passengers who went through airport security on the same day last year, which saw over 2.5 million.

The novel coronavirus has infected more than 3.6 million people across at least 187 countries and regions. More than 1.1 million have reportedly recovered from infection, while over 251,800 have died, as of Tuesday, according to the latest figures from Johns Hopkins University.

The graphic below, provided by Statista, illustrates U.S. states with the most confirmed COVID-19 cases.

U.S. states with the most coronavirus cases.Statista

The graphic below, provided by Statista, illustrates the spread of the COVID-19 virus across the U.S.

The graphic shows the number of confirmed COVID-19 cases by U.S. State as of May 5, 2020.

Centers for Disease Control and Prevention Advice on Using Face Coverings to Slow Spread of COVID-19

  • CDC recommends wearing a cloth face covering in public where social distancing measures are difficult to maintain.
  • A simple cloth face covering can help slow the spread of the virus by those infected and by those who do not exhibit symptoms.
  • Cloth face coverings can be fashioned from household items. Guides are offered by the CDC. (
  • Cloth face coverings should be washed regularly. A washing machine will suffice.
  • Practice safe removal of face coverings by not touching eyes, nose, and mouth, and wash hands immediately after removing the covering.

World Health Organization advice for avoiding spread of coronavirus disease (COVID-19)

Hygiene advice

  • Clean hands frequently with soap and water, or alcohol-based hand rub.
  • Wash hands after coughing or sneezing; when caring for the sick; before, during and after food preparation; before eating; after using the toilet; when hands are visibly dirty; and after handling animals or waste.
  • Maintain at least 1 meter (3 feet) distance from anyone who is coughing or sneezing.
  • Avoid touching your hands, nose and mouth. Do not spit in public.
  • Cover your mouth and nose with a tissue or bent elbow when coughing or sneezing. Discard the tissue immediately and clean your hands.

Medical advice

  • Avoid close contact with others if you have any symptoms.
  • Stay at home if you feel unwell, even with mild symptoms such as headache and runny nose, to avoid potential spread of the disease to medical facilities and other people.
  • If you develop serious symptoms (fever, cough, difficulty breathing) seek medical care early and contact local health authorities in advance.
  • Note any recent contact with others and travel details to provide to authorities who can trace and prevent spread of the disease.
  • Stay up to date on COVID-19 developments issued by health authorities and follow their guidance.

Mask and glove usage

  • Healthy individuals only need to wear a mask if taking care of a sick person.
  • Wear a mask if you are coughing or sneezing.
  • Masks are effective when used in combination with frequent hand cleaning.
  • Do not touch the mask while wearing it. Clean hands if you touch the mask.
  • Learn how to properly put on, remove and dispose of masks. Clean hands after disposing of the mask.
  • Do not reuse single-use masks.
  • Regularly washing bare hands is more effective against catching COVID-19 than wearing rubber gloves.
  • The COVID-19 virus can still be picked up on rubber gloves and transmitted by touching your face.