Many big US airlines are bringing in new health and safety policies for both passengers and cabin crew this week.

Other carriers around the world are also making mask wearing mandatory for when they restart flights.

While around 90% of international flights have been cancelled, airlines hope to gradually resume air travel starting this month.

From Monday, US carrier Delta said it requires passengers to wear a mask or other face covering in the check-in area, premium lounges, boarding gate areas and onboard planes for the whole flight.

American Airlines and United have also said that they will start requiring masks for passengers, along with cabin crew. The carriers say these are temporary measures as they slowly resume flights.

“We are looking out for our customers’ well-being to give them peace of mind while they travel with us,” said Kurt Stache, a spokesman for American Airlines. “We’re moving quickly on these enhancements and we’ll continue to improve the travel experience for our customers and team members as we navigate these times together.”

“Face coverings will be mandatory for all passengers, and (we) will provide masks to passengers for free,” said Maddie King, a spokeswoman for United Airlines.

But not all airlines are making passengers wear face masks. Qantas said there “are no requirements in Australia to wear masks. No decisions have been made by the Government or airlines about what measures will be put in place for travel once restrictions are lifted.”

The Australian national carrier said on its website: “While the risk of contracting coronavirus on board an aircraft is regarded as low, social distancing has been put in place across all flights.” It is currently following guidelines from Australia's chief medical officer.

When it comes to a global policy for airlines to follow, there are a number of bodies that could offer guidance including the International Air Transport Association. (IATA). "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," said an IATA spokesman.

Other measures

Airlines are bringing in a range of safety measures onboard to help prevent the spread of the coronavirus. It's unclear if these will be temporary measures or more long term.

Major pre-flight cleaning measures to disinfect heavily used areas are being widely used along with reducing the number of people on each flight.

Passengers are also being encouraged to pack their own food and drinks to decrease contact.