US airlines refused to charge for ticket exchange

Major US airlines, in order to attract more customers in a difficult period for the world's civil aviation, refused to charge for the exchange of air tickets for another date. 

United Airlines was the first to announce this change in fare policy on Sunday, followed by American Airlines and Delta on Monday. However, there are some exceptions.  

For example, United Airlines and Delta retained fees for exchanging class 1 tickets, as well as tickets for international flights. American Airlines went a little further, raising the fee for exchanging tickets for regional flights to Canada, Mexico and the Caribbean.