An airline can still provide a travel voucher but only if the customer is aware of the option to receive a refund.

Airlines Are Now Required to Issue Refunds for Flights Canceled Due to Coronavirus (Video)

The U.S. Department of Transportation has mandated airlines to refund passengers in the event flights are canceled, significant schedule changes or made, or government restrictions prevent flying due to the coronavirus outbreak.

The directive, issued Friday, comes as many airlines have been offering future travel credits, rather than refunds, amid the coronavirus pandemic. The DOT said it received “an increasing number of complaints” about the lack of refunds.

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The order applies to any flights on U.S. or foreign airlines “to, within, or from the United States.”

“Although the COVID-19 public health emergency has had an unprecedented impact on air travel, the airlines’ obligation to refund passengers for cancelled or significantly delayed flights remains unchanged,” the DOT wrote in its Enforcement Notice. “The longstanding obligation of carriers to provide refunds for flights that carriers cancel or significantly delay does not cease when the flight disruptions are outside of the carrier’s control (e.g., a result of government restrictions).”

While the notice was issued last week, the department said it would hold off on prosecuting violations immediately.

“In recognition of the fact that the COVID-19 public health emergency has had major impacts on the airline industry, the Aviation Enforcement Office will exercise its prosecutorial discretion and provide carriers an opportunity to become compliant before taking further action,” the DOT added in its notice.

However, head of the group that represents airlines around the world, the International Air Transport Association, insists that the measure isn't financially feasible.

"The key element for us is to avoid running out of cash so refunding the canceled ticket for us is almost unbearable financially speaking," Director General Alexandre De Juniac said in an online news conference, according to NPR.

An airline can still provide a travel voucher in lieu of a refund if the airline tells passengers who already received that voucher about the option to receive a refund, updates and clarifies their refund policies, and goes over the new refund policies with staff, according to the notice.