Jet fuel prices soared past $4 a gallon on world markets in the past week for the first time in history, according to the U.S. Energy Information Administration.

Prices in key world markets peaked at $4.241 a gallon in Europe the week of May 19 and reached a high in the United States of $4.171 a gallon in Los Angeles.

The fuel price increases for airlines came as oil prices on world markets peaked at around $135 a barrel last week before slipping back several dollars this week. The latest increases mean jet fuel has almost doubled in just a year, adding about $2 a gallon since the average prices of May 2007.

Most airlines have ratcheted up fuel surcharges with the increases at the pump but many say they are struggling to keep up with the rapid pace of rising energy costs.

By the end of the most recent full week, the cheapest average jet fuel price in the world was at New York Harbor, where the $3.98 a gallon rate was about 12 percent above the average price in April.