This article has been excerpted from Design and Launch an Online Travel Business in a Week by Entrepreneur Press and Charlene Davis, available from Entrepreneurpress.com.

Many types of online businesses come and go in the blink of an eye. But the trillion-dollar travel industry continues to grow by leaps and bounds, creating a big demand for specialized services.

Here are a few of today's hottest specialty travel opportunities:

Adventure Travel and Outdoor Excursions
Adventure means different things to different people. For some it might be sailing or snorkeling in the crystal indigo waters off the coast of Cancun, Mexico; others might get a thrill from petting a shark or climbing 4,000 feet in the cockpit of a Soviet jet trainer. It certainly means a lot of fun for a lot of people. Statistics provided by the Travel Industry Association (TIA) show that during the past five years, 98 million adults have taken an adventure trip--rock climbing, mountain hiking, whitewater rafting, spelunking, parasailing, skydiving and other activities. "Soft adventure" vacations are milder and may feature walking, bicycling, fishing, camping or horseback riding.

Many adventure and eco-tour operators have developed their niche because of a desire to share their passion and experience with others. Jennifer Sage, owner of Viva Travels, plans custom guided and self-guided bicycle tours in France and Italy. "I love to share my love of traveling by bicycle with others," she says. "I firmly believe there is no better way to see a country!"

Luxury Travel
Luxury traveling caters to a posh demographic and does not have any competition from the thousands of discount travel sites. Affluent customers are willing to spend more to get more, which means a luxury travel specialist will need to resonate with people who consider exotic travel to be a lifestyle.

Many upscale travelers are retaining agents who act as "travel concierges," making all the arrangements from travel and lodging to dinner reservations and theater tickets, often for a flat fee of up to $1,000. Even more well-heeled clients might opt for a members-only travel concierge like a New York City firm that charges $250,000 just to join and another $10,000 in annual fees.

Dane Steele Green of Steele Luxury Travel created a very specialized niche within the luxury travel category when he saw there was a need in the marketplace for a luxury, upscale travel company that catered to the gay community. "It's all about luxury," says Dane. "These are people who have the money to experience the finest in life, without having to book it and do all of the work themselves. That's what I do." And he does that by planning exclusive, custom-made travel packages and taking his clients to popular destinations around the world-in style.

For Women Only
Recently, Road and Travel magazine reported that women influence 85 percent of all travel decisions and comprise 40 percent of all business travelers. "Girlfriends getaways" have become a booming trend in the travel industry, spurring new start-ups like Chick Vacations, owned by Heather Hills. When she created the site in 2007, Hills wanted to show women they don't need to spend a lot of money on fancy "raft the Amazon" or "climb the Himalayas" adventure travel. "A weekend girls' getaway doesn't need to be expensive to be a great opportunity to bond with other women," she says.

Another female demographic to target is older women. According to the recent statistics provided by the U.S. Census Bureau, mature women outnumber men by a ratio of 100 to 81 (55-64); 100 to 82 (65-74); 100 to 69 (75-84); and 100 to 49 (85+). The Travel Industry Association of America predicts older female travelers will be one of the driving forces behind senior traveling in the long term.

Although spas and cruises remain popular choices for women, dozens of other special interest trips are springing up: wine-tasting in Napa Valley, making handicrafts with the locals in Costa Rica or shopping in Versailles.

Mancations

"Mancation" is one of the latest buzzwords in the travel industry, a spin-off on the girlfriends' getaway marketing phenomenon. Although the term is new, the concept isn't--as evidenced by the dozens of guy-getaway themed movies that have been around for ages.

Last year when James Hills was helping his wife, Heather, launch Chick Vacations, he discovered the field of guys getaways was virtually nonexistent online. "A lot of buzz was starting to generate, and we knew this was going to be a good subject," he says. "We took some of the same philosophy from Heather's site and applied it to the Man Tripping site to show that guys' getaways don't need to be booze-soaked orgies. There is a lot more to being a guy than sex and drinking, so I am looking forward to exploring and promoting that angle."

Mancations provide the opportunity for men to get together and bond with guys from work or old friends from college. Although golf outings, sports events and fishing trips are the mainstays of male bonding, some of the fellas are branching out with high-velocity adventures like skydiving and bungee jumping, while others opt to kick back with spa treatments and back waxes.

Honeymooners
Couples who are deeply immersed in wedding plans are often more than happy to turn over the reins of planning a honeymoon package to a travel professional. The couple generally knows where they want to go and may sometimes have a vague idea of what to do when they get there, but the rest may be up to you. Once you have a sense of their likes and dislikes you can then make some recommendations-whether it's cruising in the Bahamas, kanoodling in Hawaii or camping in the Rockies. Upon their arrival, surprise them with a spa treatment basket, champagne on ice or tickets to a special attraction. Unique personal touches and attention to details will increase the odds you'll be recommended to family and friends.

Grandtravel
"Grandtravel" is a specialized niche that is one of the fastest growing travel trends, representing more than 21 percent of all trips taken with children last year, according to the TIA. Grandparents today are not like grandparents of yesterday; greater numbers are more energetic, active, and adventurous. They don't want to stay home and look after the grandkids. Instead, they want to pack the kids up and take them along on fun-filled vacations, while leaving the parents at home to take a breather. Because geography separates many families, special trips bring grandparents and grandchildren together to strengthen bonds and create lasting memories. As an added bonus, most of the time senior and children's discounts can be factored into the package for added savings.

Disabled Travelers
Travelers with disabilities have more opportunities than ever to explore the world with the assistance of hi-tech support and creative planning. A study done by the Open Doors Organization, the TIA, and the Society for Accessible Travel and Hospital (SATH) indicates that disabled travelers currently spend approximately $3.3 million a year on travel. "Dialysis cruises" using portable dialysis equipment are planned for patients and their families; road trips are taken with wheelchair accessible vans and buses; and transportable nebulizers and oxygen cylinders are made available for travelers with respiratory problems.

When planning a tour for those with physical limitations, consider the accessibility of the facilities on your itinerary. Are there steps that will need to be navigated? Even one step could be a problem for someone in a wheelchair or using a walker. Does the museum have elevators large enough to accommodate wheelchairs? Are the restrooms in the basilica handicapped accessible? Are aisles and walkways at the quaint little antique village wide enough for wheelchairs and scooters? Are the sidewalks in the town rough and uneven?

As each country has its own standards, disabled clients traveling abroad may face additional challenges regarding transportation and accessibility. Advance research and planning are a necessity so your clients can have a safe and enjoyable trip.

Travelers with Pets
Traveling with pets is a very specialized niche that is growing quickly as demand increases and resources expand. According to TIA, more than 29 million Americans traveled with their favorite canines and kitties during the last three years. Pet lovers cross all economic spectrums, but luxury and business travelers are more likely to spend the extra cash and make the necessary arrangements to bring their beloved companions with them.

Loews Hotels was the first national hotel brand to welcome pets with their "Loews Loves Pets" program. Fido and FiFi even have their own room service menu with recipes prepared from scratch. Since then, many vacation resorts and hotels have added "pet-friendly" to their list of amenities because they realize animal lovers who travel with their pets usually have money to spend. Focusing on this particular trend has given them a distinctive edge over the competition that you can take advantage of.

There are many ways to segue into this niche. For example, you can be a pet travel concierge like Puppy Travel or a subscription-based site that provides up-to-date information for its members at Pets on the GoT. When planning trips for pet lovers you will want to map out dog-walking routes, pet-friendly restaurants, pet shops, groomers and find information about local veterinarians and other services for the discriminating pet owner.

Interested in more opportunities? Click here to view the full chapter on Travel Specialties from Design and Launch an Online Travel Business in a Week.

Charlene Davis is an accomplished writer specializing in business, retail, e-commerce, and food. In addition to numerous articles and ghostwritten publications, she is the author of Start Your Own Photography Business, Start Your Own Clothing Store, and How to Sell Clothing, Shoes, & Accessories on eBay.