This phenomenon is not new, Bender and others say. It even has a name, which was coined by University of North Carolina professor John Kasarda: the aerotropolis.

The idea is that major business centers have always occurred along major transportation routes. Rivers to railroads to highways.

Air travel is now such a critical mode of transportation, the theory posits, that airports have become a major hub of the community.

"Gateway Airports will be as important to business location and urban development in the 21st century as automobiles and trucks were in the 20th century, railroads in the 19th century and waterborne transport in the 18th century," Kasarda wrote in a 2000 article in the trade journal Real Estate Issues.

Bender points to regions around Dallas-Fort Worth's airport and Dulles International Airport, near Washington, as proof of what the DIA area could become. Both are major business and employment centers in their respective cities.

"That's what happens over 20 to 30 years," Bender said. "And we're just 10 years into this."

To get an idea of how DIA might create its own economic kingdom, it helps to remember how it started.

First, there was virtually nothing out on the plains 24 miles northeast of downtown. Then there was DIA.

Hotels and businesses specifically linked to the airport, like shipping and cargo firms, started appearing nearby.

The people who worked at the airport and those firms needed places to live. Cities such as Brighton, Commerce City and Aurora began looking to capitalize on that.

In the years before 1995, when DIA opened, Brighton had issued about a dozen building permits annually. In 1995 that number jumped to 200. And for every year after that the city has issued somewhere between 500 and 1,000 building permits.

"We have become so travel-dependent, so air-dependent," said Brighton economic development director Shawne Ahlenius. "So I think that's what's going to drive not only Brighton but the whole northeast Denver area for the next 20 to 30 years."

Commerce City issued only 18 homebuilding permits in the entire decade between 1987 and 1997. By 2003 the city was issuing 1,400 such permits a year. Most of those were for houses in the city's "northern range," a large chunk of land Commerce City annexed just west of the airport that has developments of several thousand homes each.

The airport "has helped in terms of home sales and bringing people to Commerce City to live in the newer portion of town," said City Manager Perry VanDeventer.