If unforeseen circumstances force you to re-book an international flight from the U.S., you might face a hefty change fee — as much as $500 per ticket.

But a passenger rights group has asked the U.S. Department of Transportation to adopt a $100 cap for such a fee, arguing that the charges are exorbitant for an airline industry that is now collecting record profits because of slumping fuel costs.

Change fees for international flights were as low as $50 to $100 for a nonrefundable ticket only a few years ago, said Paul Hudson, president of FlyersRights.org, a 50,000-member group that filed a petition with the federal agency this month to adopt the cap.

Instead of dropping or holding steady as airlines have reported higher profits, Hudson said, the fees have increased as demand for air travel has grown.

The U.S. airline industry collected $2.8 billion in change fees in 2013 and is expected to report even more revenue from change fees in 2014 when the latest report from the Department of Transportation is released in May.

But airlines say the fees are not excessive and are clearly described to travelers before they book flights, according to Airlines for America, the trade group for the nation’s airlines.

"FlyersRights’ petition fails to demonstrate that there has been a market failure when it comes to what airlines charge for changed reservations," said Victoria Day, a spokes­woman for the trade group. "Airline pricing is extremely transparent, and customers are aware of what they are purchasing and at what price before they buy their air transportation."

Hudson said the Department of Transportation lost the right to regulate fees on domestic flights when it deregulated the airline industry in 1978 but still can impose restrictions on international flights.

Hugo Martin, Los Angeles Times