Shippers are finding it cheaper and more efficient to use trucks, experts said. The biggest area of growth for airlines and airports is on the international side, where shipments of electronic equipment to and from Asia are increasing rapidly.
D/FW is grabbing some of the international growth.
"Before, international cargo went to only the gateway cities," said Phillips, who is executive director of Keiser Phillips Association in Seattle. "Now they're bypassing gateway cities and going to places like D/FW."
That's because those gateway cities -- Los Angeles, San Francisco, New York, Chicago and Miami -- are becoming overcrowded, said Liying Gu, senior manager of economic affairs and research for Airports Council International-North America.
Through the end of August, the most recent data available, D/FW's cargo shipments are up 1.3 percent from the same period last year. International cargo accounts for 1 of every 3 boxes shipped at D/FW.
For all of 2004, total cargo increased 11 percent in a year, thanks to a 28 percent boost in international cargo.
Bill Frainey, who oversees cargo operations at D/FW, is focused on growing the international side. He's proud of a Department of Commerce statistic that shows international air cargo growing nearly 12 percent at D/FW since 1996.
He estimates that two or three airlines are seriously looking at starting cargo service at D/FW. But the decision won't be made overnight.
Frainey spent four years wooing Cathay Pacific. The Hong Kong-based carrier is now flying into D/FW three times a week and plans to double that by 2007, said Frainey, an assistant vice president at the airport.
American is glad to have Cathay Pacific.
"Anytime you have that kind of capacity coming in, it will tend to attract business into your region," Brooks said. "For a carrier such as ours with a network like we have, it's also a great opportunity for us to feed them traffic."
Cathay Pacific will bring a lot of high-tech electronics, clothing and other consumer goods. It's similar to what American and other passenger carriers haul in the belly of their planes.
Travelers likely never think about some of the unusual cargo riding in the belly of planes just below their feet, experts said.
Southwest Airlines says it moves a lot of crabs out of Houston and New Orleans and Dell computers out of Austin.
Consider American's most unusual items:
Sea urchins from South America, through D/FW Airport, to Japan, where they're treated as aphrodisiacs.
Blood, human organs and bodies -- "people don't always die where they want to be buried," Brooks said.
Monkeys and leopards transferred from one zoo to another.
Cash moved from the Federal Reserve Banks.
Rock band equipment for the Eagles and U2 shipped for concerts.
The actual film for new movie releases from Hollywood.
The largest source of cargo for American and other passenger airlines is mail.
"We're heading into a busier season as we get into the holidays," Brooks said. "Everyone's mailing their Christmas cards."
The airline also sees more mail shipments at the end of each quarter as financial reports are sent to stockholders.
American lost the ability to deliver mail for about a month in early 2005, partly because of its poor on-time record.
But American tweaked a couple things and got the business back, Brooks said.
"It's not glamorous, just basic blocking and tackling," like the unheralded grunt work done on the football field, he said. "You can't put it on a bumper sticker what we did."
American looked at the loss of its mail service and said, "This is good business for us," Brooks said. "If we can't meet the Postal Service's expectations, it will go away. So let's try to figure out a way to deliver their products smarter and better."
Alliance Airport has also seen growth over the past few years.
Cargo has grown 30 percent during the first 10 months of 2005 over the same period last year. The 15-year-old airport is headed for its second-best cargo year, sending and receiving 211,000 metric tons in 2005.
The largest share of cargo comes through FedEx, which opened a hub at Alliance in 1997.
Fifty metric tonnes of cargo will arrive at DFW on each of the three weekly flights from Hong Kong.
North Texas' low international profile is one of many challenges officials face as they labor to attract new flights to foreign destinations.
Yangtze River Express will land at DFW International Airport four times weekly beginning May 22.
On Thursday, American will launch 16 daily flights from Love Field, its first North Texas service away from D/FW in more than four years.