A US Senate panel slammed US airlines over so-called "junk fees" related to seat selection and luggage, multiple media outlets reported Tuesday.

American Airlines Group (AAL), Delta Air Lines (DAL), United Airlines Holdings (UAL), Frontier Group Holdings (ULCC) and Spirit Airlines made a combined revenue of $12.4 billion from seat fees between 2018 and 2023, according to a report from the Senate Permanent Subcommittee on Investigations, various media outlets reported.

The subcommittee's chair, Senator Richard Blumenthal, D-Connecticut, said airline executives have been called to testify at a hearing on Dec. 4, the reports said.

"Delta looks forward to the continued dialogue with the subcommittee including appearing at next week's hearing," Delta said in a statement emailed to MT Newswires. "Next to safety, Delta's number one priority is taking care of our people and our customers and includes our commitment to providing a choice of fare products that best meets our customers' specific travel needs."

The trade group Airlines for America told MT Newswires it was "deeply disappointed" with the report. "The report demonstrates a clear failure by the subcommittee to understand the value the highly competitive US airline industry brings to customers and employees."

"Frontier works every day to increase consumers' access to affordable air travel and to ensure that it provides the best possible value to its customers," Frontier told MT Newswires.

"We respectfully disagree with numerous statements and conclusions contained in the report," Spirit told MT Newswires. "We look forward to explaining our position."

United declined comment to MT Newswires. American Airlines referred inquiries to Airlines for America, the trade group.