WASHINGTON – The government would standardize the way airlines disclose fees for basic services like checked bags, seat assignments and ticket changes so that passengers can more easily comparison-shop the full cost of flights under a bipartisan Senate bill introduced Wednesday.

The proposal is part of an airline policy bill sponsored by Sen. John Thune, R-S.D., chairman of the Senate Commerce, Science and Transportation Committee, and Sen. Bill Nelson, D-Fla., the committee’s senior Democrat. It would extend the operating authority of the Federal Aviation Administration through Oct. 1, 2017. That authority is due to expire March 31.

The bill would require the Department of Transportation develop a way to display fees that’s easy for consumers to understand and require that airlines and ticket agents use the system. A report last year by the committee’s Democratic staff found that airline fees, especially for things like ticket cancellations or changes, are often hidden from consumers while shopping fares online or disclosed in lengthy paragraphs of tiny type-face that’s difficult to read.

Airlines would also have to return fees for bags that are lost or delayed more than six hours after the arrival of a domestic flight, and more than 12 hours after the arrival of an international flight under the bill. Airlines would also be required to automatically refund fees for services purchased but not received by passengers. Examples would include things like advance seat assignments that turn out to be unavailable or early boarding that isn’t provided.

The consumer provisions were a compromise that doesn’t go far enough for some senators. Sens. Ed Markey, D-Mass., and Richard Blumenthal, D-Conn., also introduced a proposal to prohibit airlines from charging fees for basic services “that are not reasonable and proportional to the costs of the serves provided.” The proposal is likely to be one of several amendments offered this week when the committee is scheduled to take up the aviation bill.

Missing from the bill is any effort to wrest air traffic control operations from the FAA and spin them off into a private, nonprofit corporation. An FAA reauthorization bill that would have privatized air traffic control services was passed last month by the House Transportation and Infrastructure Committee on a mostly party-line vote with Democrats unanimously opposed. The bill has the backing of the committee’s chairman, Rep. Bill Shuster, R-Pa., and the airline industry, but it was sidelined by House leaders in the face of opposition from other powerful GOP lawmakers and influential segments of the aviation industry.

Eighteen months is an unusually short time-frame for an FAA reauthorization bill. But Thune and Nelson are pitching their bill to their House counterparts as a means to make important policy changes while continuing to work on politically difficult question of whether to pass a privatization bill. Privatization supporters say it would make the funding of air traffic control operations more stable and speed up the modernization of the air traffic system from one based on radar to one based on satellite technology.

Besides provisions aimed at protecting airline passengers, the Senate bill also requires the government to set product safety standards for small drones and that consumers and hobbyists take an online safety knowledge test before they fly their unmanned vehicles. The Department of Transportation is directed to adopt an international ban on cargo shipments of rechargeable lithium on passenger planes. FAA tests have shown the batteries are capable of igniting intense fires.

The bill also authorizes greater use by the FAA of the employees of manufacturers as surrogates for government inspectors in order to speed up the safety certification of planes and aviation equipment. Manufacturers have complained they lose business to overseas competitors because they have to wait too long for FAA approval of their products.

Airlines for America, a trade association for major airlines, said in a statement that the Senate bill tries to regulate prices and services even though the industry has been deregulated since 1978. The result, the statement said, could be higher prices for consumers.