U.S. ports logged higher cargo movements in April from a year ago, with the Port of Long Beach, California, reporting that its tonnage rose to the highest level for the month in six years.

Volume at the neighboring Southern California ports of Long Beach and Los Angeles increased, with Los Angeles’ rising to its second-busiest month on record.

Container volume at the Southern California ports of Los Angeles and Long Beach declined in February from a year ago because of backed-up congestion related to labor issues, the two said.

The South Carolina Ports Authority posted 18% container growth in February for the second consecutive month, SCPA reported last week.

The Port of Los Angeles has implemented a new program to speed cargo to clear the backlog of containers and move shipments faster in the future.

West Coast port operators strived to accelerate operations last week after a tentative contract agreement was reached, but carrier executives and experts see hurdles before the supply chain gets humming again.

Shipper and railroad executives joined senators at a Washington hearing to bemoan the negative global consequences of West Coast port delays and the U.S. infrastructure investment shortfall.

California truckers, stung by millions of dollars in delay-related costs, have asked the Intermodal Association of North America to rule that port carriers should not be required to pay those fees accumulated since November.

The shift of seaborne cargo to jets’ bellies shows how Asian airlines including ANA Holdings Inc. and Cathay Pacific Airways are benefiting from gridlock at ports in California and Washington state.