A key measure of jet fuel costs jumped 4.1 percent in the past week, showing fuel prices for the airlines are soaring again and suggesting that surcharges for shippers are on their way up.

The Lufthansa Cargo Current Fuel Price Index hit 377 at the end of the second of April, up 15 points from the week before and 34 points - or 10 percent - since March 24.

The measure was at its highest level since the spike in fuel prices last fall pushed the index over 400.

The index, closely watched by many airlines as a trigger for fuel surcharges, has grown more than 26 percent since early December.