In a 55-page report, the majority staff of the Senate Permanent Subcommittee on Investigations released on Tuesday its findings after a year-long inquiry into five U.S. airlines’ ancillary fees, which the report said have led to higher costs and worse experiences for consumers and, in some cases, tax avoidance by the airlines.

A Senate subcommittee on Tuesday slammed U.S. airlines large and small over fees to pick seats on flights. Between 2018 and 2023 American, Delta, United, Spirit and Frontier brought in $12.4 billion in seating fees,