Mary Altaffer/AP

U.S. airlines rang up more than $1.7 billion in baggage fees in the first six months of the year, the most ever collected in that period.

Delta Airlines collected the most in baggage fees with nearly $430 million from January to June, according to a report the Bureau of Transportation released Tuesday. United Airlines came in second with $351 million in baggage fees.

From carry-on to oversized items, U.S. airliners are raking in record revenues, a rare bright spot in an industry now suffering turbulence from soaring oil prices and rising labor costs.

In 2007, the airlines paid an average of $2.09 a gallon for jet fuel. The next year, prices spiked 46 percent to $3.06. During the first seven months of this year, airlines have paid an average of $2.96 a gallon.

The hardest hit has been American Airlines, which filed bankruptcy protection in 2011. American is locked in a bitter labor dispute with pilots, which has contributed to delays, cancellations and fury among passengers. Earlier this month, American was forced to cancel 300 flights in one week.

But American's $25 luggage fee has helped the ailing airline rake in more than $288 million so far this year, according to the Bureau of Transportation, which is part of the U.S. Department of Transportation.

"The travelers who haven't gotten used to these fees need to get used to them quickly because this is a huge stream of revenue for the airline industry and it is not going anywhere," says Genevieve Shaw Brown, ABC News' travel and lifestyle editor. "If anything, there will be more fees in the future."

While most passengers find baggage fees costly, there is one airline that is taking customer concerns to heart. Southwest Airlines is promoting its "bags fly free" policy as a way to gain business. Southwest will allow customers to check two bags per passenger for free. JetBlue allows one free bag per passenger.

U.S. airlines also collected an additional $1.3 billion in fees for canceling or changing a reservation during the first six months of the year, according to the Bureau of Transportation.

The Associated Press contributed to this report.