Many airlines have suspended or canceled flights amid a surge in coronavirus cases, reports Reuters.
Flights to China and Hong Kong on American Airlines have been extended through April 24, on Delta through April 30 and on United Airlines through April 23.
Delta on Monday also said it would allow travelers holding tickets for travel to any destination in March and April to change or cancel their flight without paying a hefty change fee regardless of when the ticket was purchased.
The broad fee waiver is the first by a major U.S. airline.
"As concerns continue about the coronavirus known as COVID-19, we are doing everything we can to ensure the safety and security of our customers and employees,'' Delta said in announcing the policy. "We have adjusted flight schedules to affected areas, waived many change fees and are working with customers to adjust travel plans, using relationships with other airlines when needed.''
Many airlines have also trimmed flights after demand fell because of the virus, which originated in Wuhan, China, and has infected more than 114,000 people and killed more than 4,000.
The coronavirus has taken a large toll on airline stocks, which have tumbled as more cases emerge.
Airline bookings in North America were down about 8% in the last week of February and by “mid-teen” percentage points in the first week of March, per a Credit Suisse note published Monday.