I have written a fair bit about bootstrapping, and by now, readers know my bias towards entrepreneurs who achieve more by raising less money. In this column, I am introducing you to two online travel entrepreneurs who have built substantial revenues with very little investment: Cree Lawson, founder of Travel Ad Network, and Beatrice Tarka, founder of Mobissimo.

New York City-based Travel Ad Network is the largest Vertical Ad Network in travel. At a time when text ads were all the rage, it differentiated itself by pioneering graphical advertising that enhanced ad quality and made ads more profitable for publishers as well as advertisers. TAN sells ads on behalf of a large number of publishers.

TAN reaches users across 50 Web publishers, including Lonely Planet, Kayak, RandMcNally, Groople and many others. Top TAN advertisers include American Express (nyse: AXP - news - people ), Vacations to Go, Best Western and Netherlands Tourism.

Today, TAN reaches 14.4 million unique monthly users in the U.S. and a total of 22.5 million worldwide. Last February, the company added Canadian and U.K.-centric travel sites to expand outside the U.S.

TAN closed a $15 million Series A financing round led by Rho Ventures, Village Ventures and individual investors in April, giving the company an estimated $50 to $75 million valuation. Prior to this round, the company had raised minimum financing. In June 2007, Michael Thomas, an online travel investor and entrepreneur, invested around $1.2 million in TAN. It was the first and only time TAN raised any outside money since its inception in 2003.

For the last three years, TAN has been running at break even. But with the new funding, it looks to aggressively pursue growth opportunities. That means adding publishers, sales reps and advertisers. (For more on the subject, see my interview with CEO Cree Lawson.)

Beatrice Tarka has a similar story. She is Italian and Polish by birth and French by citizenship. She has leveraged her international background and passion for travel and technology to build a vertical search engine company, Mobissimo.

Since its launch in October of 2003, San Francisco-based Mobissimo has created a staunch following of "MobiFans." With a sweet spot in international travel, it has been very successful catering to a niche other travel sites have largely neglected.

Mobissimo indexes a large number of low-cost airlines, such as JetBlue (nasdaq: JBLU - news - people ), EasyJet and Ryanair (nasdaq: RYAAY - news - people ), and online travel agencies and consolidators, including Lessno, Lastminute.com and Travlguru.

But what exactly gives Mobissimo an edge? Its search tool called OneBox Search lets users enter all their itinerary information in one search field as opposed to filling out several online forms. A user types in the departure city, destination and travel dates, such as "San Francisco to Rome March 18-28" directly in the search field. "You can type any combination you like and you don't have to know the airport abbreviation to launch your search," Tarka says.

Tarka and Mobissimo's other co-founders plowed their own money into the company while they developed the technology and early business model. In April 2004 they received a little over $1 million in venture capital from Index Ventures, Cambrian Ventures and Benhamou Global Ventures.

Tarka says Mobissimo's revenues have crossed $10 million, and the company has been profitable since it received the VC infusion. (See my interview with Tarka here.)

The online travel market, which is expected to reach $128 billion in revenues by 2011, has numerous niches that have attracted a large number of entrepreneurs. Besides Lawson and Tarka, there are several other entrepreneurs who are bootstrapping travel start-ups.

What I like about these start-ups is that they are building negotiating leverage for themselves, as evidenced in the Series A valuation that Travel Ad Network received.

Late-stage money is always abundant in the venture capital market, but good, fundable deals are relatively rare. Entrepreneurs can even cash out a portion of their holdings in a private transaction at a strong valuation, if they choose to bring VCs in later in the game. And some start-ups, such as competitors Kayak and SideStep, have banded together and done a roll-up.

Given the state of the American economy, it is essential for entrepreneurs to create new businesses to rejuvenate the system. Less than 1% of entrepreneurship in the U.S. is funded by venture capital. These niche online travel businesses highlight a segment of the market where entrepreneurship is active and not dependent on venture capital to get itself off the ground.

We need more such segments--and many more entrepreneurs playing in them.

Sramana Mitra is a technology entrepreneur and strategy consultant in Silicon Valley. She has founded three companies and writes a business blog, Sramana Mitra on Strategy. She has a master's degree in electrical engineering and computer science from the Massachusetts Institute of Technology.