More: "Passengers deserve to get their money back when an airline owes them " without headaches or haggling," Transportation Secretary Pete Buttigieg said in a statement.

Under the new rule, passengers will be entitled to refunds if there is a "significant change" to their flights. These include:

Departure or arrival time that moves by more than three hours domestically or six hours for international flights
Being downgraded to a lower class than originally purchased, as from first class to economy
Change of departure or arrival airport
Increase in number of connections
Changes to connecting airports or planes flown if they are less accommodating for people with disabilities

Travelers will also get refunds for checked bag fees if the bag is lost and not delivered within 12 hours of a domestic flight's gate arrival. International flights will have from 15 to 30 hours to return a lost bag, depending on their length.

Anyone who pays for a service, such as in-flight Wi-Fi or entertainment, and doesn't receive it will also get their money back.

In addition, DOT made changes to make it easier for the passengers to receive the money they're owed by requiring prompt automatic refunds in cash or through the original form of payment. Buttigieg said during a news conference at Ronald Reagan Washington National Airport Wednesday that the bulk of the new requirements will go into effect in about six months.