The percentage of seats filled on flights worldwide rose in August to match a record high of 83.4%, a signal that commercial airlines are squeezing more revenues per flight.

The percentage rate, known in the aviation industry as the "load factor," matched the previous high mark set in July 2011. It was the result of demand growing faster than capacity, according to a report by the International Air Transport Assn., a trade group for the world's largest airlines.

Among domestic carriers in the U.S., the opposite was true: Capacity grew twice as fast as demand. Still, the nation leads all countries with the highest load factor for domestic travel, 85.8%, according to IATA.

"August was a positive month for passenger travel,” said Tony Tyler, IATA’s director general.

The report said that, so far, the federal government shutdown is not expected to impact the operation of commercial flights but it could dampen demand.