Although oil prices have dropped over the past few weeks, U.S. airlines have no immediate plans to reduce fuel surcharges that they tack on to the price of a ticket.

Most carriers have imposed several increases in their fuel surcharges -- they range up to $170 per round trip in the United States and more for international flights -- on top of fare hikes.

Fuel accounts for up to 40 percent of the budget at many of the biggest airlines, topping labor as their biggest single cost.

U.S. airlines increased their fuel surcharges several times as oil roared past $100 a barrel and beyond, but they haven't reduced the fees as oil prices slid 30 percent since their mid-July peak.