Air freight rates for trans-Atlantic shipping into the United States jumped 6.5 percent in April, according to an independent index of cargo pricing.

The Bank of America Securities index showed April's rate growth was slower than the 7.9 percent expansion in the first quarter but still a strong increase on the major air trade route that saw rates grow a modest 2.3 percent last year. "We sense carriers have managed capacity well on the route and most forwarders saw margin expansion in this segment in the first quarter," the investment house said. By contrast, eastbound shipment rates out of the United States to Europe slipped 0.4 percent in April and are flat this year.

The Atlantic pricing is holding up better for carriers than Pacific pricing, according to Bank of America. Rates for air shipping out of the United States to Asia fell 2.1 percent in April, the fifth straight monthly decline on what had been a strong route for freight carriers. Inbound shipment prices were off 1 percent in April.