A new measure signed into law this month will require airlines to refund baggage fees when bags are delayed.

With the new law, "passengers won't have to spend a ton of time tracking down a refund when the airline doesn't deliver," according to U.S. Sen. John Thune, chairman of the Senate Commerce committee, during remarks on the Senate floor this month.

The measure in a Federal Aviation Administration re-authorization extension bill signed into law this month directs the U.S. Transportation Secretary to issue regulations on the matter within a year.

The new regulations would require an airline to "promptly provide to a passenger an automated refund for any ancillary fees paid by the passenger for checked baggage" if the bag is not delivered within 12 hours of arrival of a domestic flight, or within 15 hours of arrival of an international flight. The passenger would need to notify the airline of the lost or delayed baggage to get the refund.

November 18, 2014 Atlanta - Travelers wait at baggage claim area at Hartsfield-Jackson International Airport on Tuesday, November 18, 2014. HYOSUB SHIN / HSHIN@AJC.COM

Credit: Kelly Yamanouchi

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Credit: Kelly Yamanouchi

Atlanta-based Delta Air Lines charges $25 for a first checked bag and $35 for a second checked bag on domestic flights.

As it stands now, if a bag is delayed more than 12 hours on a Delta flight, the passenger must apply online for a rebate. The rebate would be a $25 electronic travel voucher — not cash.

If two checked bags are delayed, the maximum rebate from Delta is a $50 travel voucher — less than the total $60 in fees for two checked bags. Those whose bags that are permanently lost can get more compensation, according to Delta.

Southwest Airlines, the second-largest carrier at Hartsfield-Jackson, allows passengers to check two bags for free.

U.S. airlines collected more than $900 million in baggage fees in the first quarter of 2016, according to the U.S. Bureau of Transportation Statistics. American Airlines collected the most baggage fees among U.S. airlines, with $262.5 million in baggage fees in the quarter. Delta was in the No. 2 spot with $197.7 million in baggage fee revenue in the same period.