(FSB Magazine) -- David and Renée Dillinger, co-founders of Ouside the Box, are breaking big with their noise-canceling headphones for air travelers. Ever since the two, whose business sells travel gear, changed the focus of their marketing from airlines to general consumers, sales have soared - from $15,000 in 2002 to $2.5 million in 2005.

SOUND IDEA: David, 40, a commercial pilot, and his wife, Renée, a former flight attendant, founded Outside the Box in Pineville, N.C., in 2001 to sell blankets, pillows, and other cabin comforts to airlines. But when he designed PlaneQuiet, a low-cost alternative to Bose's popular $299 noise-canceling headphones, he created a product with mass appeal. The $54.95 headsets - marketed through travel stores and the couple's website, protravelgear.com - became the firm's biggest seller.

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ASCENT: Outside the Box now sells more than 300 products, from portable diaper-changing stations to seatbelt extenders. But its headphones continue to drive growth; in January, Home Depot began selling a John Deere-licensed version. The Dillingers expect the deal to double revenue this year to $5 million.

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