Maybe timing is overrated.

DFW International Airport was building a new terminal and Skylink people-mover when terrorists struck the U.S. on 9/11.

Local leaders decided to continue the $2.7 billion program, betting that air travel would soon recover. But setbacks followed, including airline bankruptcies, recessions and a financial crisis. DFW Airport ended 2010 with fewer international passengers than when Terminal D opened five years earlier.

Then the local economy roared back, American Airlines restructured and the international terminal helped drive a real growth story.

Today DFW faces another major decision. With the airport setting passenger records and American looking to grow even more, when does DFW expand again? Perhaps as important, how does it grow next time?

“This is one of the most difficult questions we face,” said Tim Skipworth, vice president of airport affairs and facilities for American. “We’ve been looking at how DFW should develop for about four years, and we’ve probably looked at over 100 different options.”

The biggest hang-up isn’t the money, which could reach $3 billion for a new terminal. It’s the design of DFW Airport, he said.

With five separate terminals and a highway between them, DFW is ideal for originating and departing passengers. But connecting customers account for almost 60 percent of total traffic. They and their luggage often must be transported to another terminal, which can be slow and costly.

“There are five separate baggage systems, five front doors, many check-in counters and many security checkpoints,” Skipworth said. “All that makes operating a connecting hub a challenge.”

Both the company and region have much at stake. DFW is American’s largest, most profitable hub, and the Fort Worth-based carrier plans to funnel more traffic through it. American will soon add 100 daily flights, expected to account for much of its growth in 2019.

Late last month, after Japan and the U.S. agreed to open new slots into Tokyo’s Haneda Airport, American requested four routes. No. 1 and No. 3 are from DFW — an indication of how American’s future runs through here.

The airport has often been called the economic engine of North Texas. It supports 228,000 jobs and a $12.5 billion payroll, according to DFW. It’s also a major lure for relocating and expanding companies, especially those with a global view.

In 2004, before Terminal D opened, DFW travelers could fly to 33 international destinations. Today, there are 62 such locales, and international passengers have increased 70 percent since 2009.

How to keep the momentum going? Never fall behind, said Sean Donohue, CEO of DFW Airport.

“We’re a part of this region’s growth, and we always have to stay ahead of it,” Donohue said. “We can never be a constraint.”

The airport is adding 15 satellite gates at Terminal E, which will be used largely for American regional jets. It’s adding four gates at Terminal D and has other short-term options, if necessary.

That’s probably sufficient for five or six years, Donohue said. But the lasting solution is another terminal with about two dozen gates.

Both DFW and American agree that the gates will be needed by 2025. And it takes about five years to build a new terminal.

“So the clock is ticking, and we have to come to a decision in the next couple of months,” Donohue said. “We can’t find ourselves ever short of gates at this airport. We just can’t allow that.”

American generates about 84 percent of passenger traffic at DFW, so it covers much of the airport costs through terminal rents and landing fees. Passengers do their part by paying a $4.50 facility charge for each departing flier.

Airports around the country are launching major capital plans to upgrade and expand facilities. They include a $15 billion program at New York’s JFK and a nearly $12 billion plan at Los Angeles International. In Atlanta, Hartsfield-Jackson has a $6.2 billion capital project, according to a DFW presentation in November.

Donohue sees Atlanta as a major competitor because the region often recruits many of the same companies, and Delta has even more traffic than American at DFW. Atlanta is also a benchmark for American because the hub has some of the lowest costs in the industry.

In costs per enplanement, DFW ranked near the middle of 18 airport hubs. It was more expensive than Atlanta, Denver and Charlotte, and about the same as Houston’s Bush, DFW reported in its 2019 budget.

DFW’s gross debt service has been growing, in part because it recently renovated three terminals, a $2 billion investment. That has been offset by growing traffic and the facility charges that passengers pay.

DFW has among the highest leverage in the industry, Moody’s Investors Service wrote in October. But it has a strong credit rating and stable outlook, and analysts said the airport could handle the debt needed for a new terminal.

Donohue supports a Terminal F, long planned for a greenfield across from Terminal E. Because it’s empty land, the construction wouldn’t disrupt airlines or customers, and the area wouldn’t have to be secured, another savings, he said.

While the site has advantages, Skipworth countered that it would spread out the airport even more. Ideally, American and DFW will find a way to get more gates and improve connections — “and without raising costs so much that we can’t afford to grow there,” he said.

“We’re going to make a substantial investment in DFW,” Skipworth said. “It’s just a matter of figuring out the smartest way to do it.”