Citing the soaring price of jet fuel, several foreign airlines began raising passenger fares or adding fuel surcharges.
Swiss International Air Lines last week increased fares 3% for flights originating in Switzerland.
For other flights, the increases will vary "depending on similar measures taken by competing airlines," the company said.
Air France, Austrian Airlines Group, British Airways, Qantas and Singapore Airlines also announced surcharges on various routes.
Several times this year, U.S. airlines tried and failed to increase fares up to $10 per round trip across the board, although some maintain the higher fares on routes where competitors adopted increases.
In other airline news:
* American and Mexicana airlines have begun code-sharing on each other's flights between the U.S. and Mexico and offering a reciprocal frequent-flier arrangement.