How Hipmunk Gained Traction As the Go-To Flight-Search SiteThe San Francisco-based service puts a more streamlined spin on the age-old agony of booking passage. Plus, a look at other game-changers in the travel space.

Whether you're the type who prefers the journey or kvells over the destination, there's a good chance the experience of booking travel leaves you feeling twitchy. In need of many a plane ticket to get to college debate tournaments, Adam Goldstein, a self-professed flight industry nerd who knows "the three-letter city codes for more places than I care to mention," often found himself frustrated by the booking process.

So Goldstein approached friend Steve Huffman, co-founder ofreddit, about starting a company that would improve travel search. Even if they could just capture a small share of the travel market, the pair figured the company had big potential. Total U.S. spending on tourism during the fourth quarter of 2010 alone topped $1.4 trillion, according to the Bureau of Economic Analysis.