Cargo traffic for U.S. airlines grew at its sharpest rate in a year-and-a-half in February, advancing 6 percent on the strength of expanding trans-Atlantic trade, according to data from the U.S. Air Transport Association.

The cargo business on Atlantic lanes, where the weaker U.S. dollar has spurred exports, grew 12.2 percent in February, the largest increase on that key air trade corridor since October 2004.

Domestic air cargo business also accelerated in February, growing 3.8 percent after expanding 3.1 percent in January. The increase was the largest expansion in a single month on the domestic side since June 2006, although there already are signs that the domestic traffic may be slowing.

The February increases came before the sharp run-up in jet fuel prices that has led to higher fuel surcharges. And UPS this week issued a warning that its domestic parcel business has been turning downward in recent weeks.