The founder of an innovative website with low fares who took on United Airlines and won says he is glad to hear the feds are finally going after the big carriers.

The Justice Department sent subpoenas to several major airlines -- including United (UAL), American (AAL) and Southwest (LUV)-- as part of an investigation into "possible unlawful coordination" to control capacity to keep ticket prices high.

"I'm very happy to hear the Justice Department is doing this," Aktarer Zaman, who created skiplagged.com, told CNNMoney.

"There's a natural motivation for businesses with huge market power to maintain the power and/or use it to maximize value," he added. "It would not be surprising to see that the big airlines are collaborating in ways to drive up airfare."

Zaman is a 20-something wunderkind who founded Skiplagged.com, which uses a little-known travel secret to help fliers get cheaper fares than are available elsewhere. Skiplagged taps "hidden city" fares to book flights with connections, but the traveler never actually goes to the destination city. The connecting city, or layover city, is actually the destination.

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United Airlines and Orbitz claimed it was illegal and sued Zaman. But they lost -- Orbitz settled and the judge threw out the United lawsuit in May.

"As of now, there's no lawsuit against Skiplagged," said Zaman. "It's too late for United to appeal. If they want to sue Skiplagged, they have to start fresh."

He said the fact that United sued him "proves that at least one of the big airlines wishes to have fine control over capacity."

Meanwhile, Zaman says his web site has surged in popularity.