WASHINGTON — The government should crack down on airline fees for things like seat reservations, checked baggage and ticket changes or cancellations, which are often unfair or hidden from consumers, according to a Senate report released Thursday.

The report, which is based on an investigation by the Democratic staff of the Senate commerce committee, says there appears to be no connection between the price of checked bag fees and the costs incurred by the airlines.

“For example, many airlines charge a fee for a second checked bag that is substantially higher than the fee for the first checked bag, even though there appears to be no cost justification other than increased profit for doing so,” the report said. It recommends that the Department of Transportation, which has the power to investigate and prohibit “unfair or deceptive” practices in the airline industry, investigate whether bag fees should be tied to actual costs.

The report also says that five airlines surveyed by committee staff — United, Delta, American, Hawaiian and Spirit — charge consumers a flat fee for changing or canceling a ticket no matter how far in advance of a flight the changes are made. Further, it's very hard for consumers to find information on airline websites on the cost of change and cancellation fees, the report said.

Change fees should be limited to “a reasonable amount tied to lead time prior to departure and a maximum percentage of the original fare paid,” the report said.