Several commercial airlines in the US including the American Airlines, the Delta Airlines and the United Airlines on Thursday announced that they have made it mandatory for passengers and crew members to wear masks in their flights.

The announcement comes days after three European airlines - Lufthansa Airlines, Swiss Airlines and Austrian Airlines - made masks mandatory for their passengers during their flights.

The Jet Blue and the Frontier Airlines from the US had also made similar announcement early this week.

The Southwest Airlines, which is the only major airlines left in the US to do so, on Thursday said that an announcement in this regard is coming.

The American Airlines said that starting May 11, it will require all customers travelling to wear a face-covering (or mask) while on board the aircraft.

This new requirement is part of the airline's ongoing commitment to prioritizing customers' and team members' wellbeing in the face of the coronavirus (Covid-19) pandemic, it said.

Flight attendants would be required to wear masks from May 1. 'We ask customers to bring their own masks or face-coverings they're comfortable with when they travel. American is working to procure face masks and hand sanitizer as a supplement,' said Kurt Stache, senior vice president of customer experience, American Airlines.

Delta said that starting May 4, all customers are required to wear a face mask or appropriate face covering when travelling with it. 'We believe this change will give customers and employees some additional comfort when travelling with us,' said Bill Lentsch, the chief customer experience officer of Delta Airlines.

The United Airlines said that it will provide masks to all its passengers. 'Our flight attendants are required to wear masks on board and, beginning in early May, we will make face masks available to our customers as well,' it said.

A union for flight attendants welcomed the move. 'We're happy to see airlines taking action to require masks or face coverings for passengers, crew and other frontline employees,' said Sara Nelson, the head of the Association of Flight Attendants-CWA.

Congressman Oeter DeFazio, chair of the House Committee on Transportation and Infrastructure, on Thursday urged the FAA to require masks or other face-coverings for all crew-members and passengers on US flights.

'I further urged him to require airlines to adopt reasonable, sound procedures for ensuring that passengers are spaced at safe distances from one another, given new medical findings regarding the transmissibility of this insidious disease,' he said.

'I believe, these measures are not only well within the FAA's jurisdiction, but are also essential to protect frontline airline employees as well as the members of the flying public who still must travel during the pandemic,' DeFazio said.