The Supreme Court on June 1 barred states from regulating airline fare advertising, saying it's the federal government's job to make sure consumers are not duped.
The 5-to-3 ruling said the federal Airline Deregulation Act of 1978 preempts states from enforcing laws to protect consumers against false or misleading ads.
The decision coincidentally was handed down at a time when the airlines are offering special low fares.
In a pair of decisions on another topic, the court made it harder for states to keep out garbage and hazardous waste from other states.
The court voted 8 to 1 to strike down a disposal fee Alabama has imposed on out-of-state hazardous waste while exempting such waste generated within its borders.
And by a 7-to-2 vote, the justices invalidated a Michigan law that barred private landfill operators from accepting solid waste generated anywhere but in the county where the disposal sites are located.
The court said both states had unconstitutionally interfered with interstate commerce.
In other action, the court:
* Agreed to study a redistricting battle in Ohio, a dispute that could lead to an important ruling on minority voting rights. The court will consider reinstating a redistricting plan adopted by a GOP-controlled board for the Ohio General Assembly.
* Refused to kill a suit against Jewish groups and Los Angeles officials accused of stopping a man who claimed the Holocaust was a hoax from taking part in a library conference.
* Rejected an attempt by the Chicago Tribune Co. to avoid bargaining with a union the newspaper accused of racial bias.