There's no sign on the door of this business on a busy street in Manassas, but customers know where to find it, and they know what's offered inside: an airline ticket to El Salvador, a bus trip to Mexico, a way to wire money home or even help filing those unfamiliar-looking income tax forms.

And they know that inside the cramped office of Air World Travel & Training Corp., the help they need will be delivered in the reassuring rhythms of Spanish.

A few miles away, in Historic Manassas, customers go to Junction Travel Agency -- its window decorated with a globe and model of a cruise ship, looking for Australian honeymoons or adventurous trips to South Africa.

As Prince William County and the region change demographically, attracting both Hispanic immigrants and high-income families, so do its travel agents. The businesses have had to adapt as many of their customers gravitate to Orbitz, Expedia and other online means of arranging their own trips. Agencies like Junction discovered they could answer more requests for high-end excursions while others like Air World sprouted up around the region to serve niche markets -- such as helping immigrants navigate their new communities and visit their old ones.

According to a report by the Travel Industry Association of America, Hispanic travel volume nationally increased 20 percent, to 77.1 million people taking trips, just between 2000 and 2002. A majority of those trips were for leisure, and 43 percent of them involved traveling to visit friends or relatives.

Over at Air World, where the sounds of a radio tuned to a Spanish-language station fill the air, airline tickets are still a major part of the business. The company serves the county's growing Hispanic population -- in the 2003 Census it accounted for 14.5 percent of the county's residents. The mostly Hispanic immigrant customers rarely have access to the Internet, some can't read and some may simply feel more comfortable dealing with an agent who speaks their language, said Angie Peoples, president of Air World, which has its main office in Alexandria.

Some of her customers don't have credit cards and prefer to stop by the office so they can pay in cash, said Peoples, who is Peruvian.

When Salvadoran sisters Sara and Maria Canenguez came in the other day, they plunked down a thick wad of cash to pay for tickets to La Paz, El Salvador, where they lived until they moved to Manassas four years ago.

They went to Air World because "it's easier with the language," said Maria Canenguez, 24.

Sales executive and jack of all trades Luz Cavero rattled off a list of services the agency offers: notarizing documents, sending money wires across the globe, preparing income tax returns. Most important for many of her customers, she inspects passports and visas to make sure all documents are in order, warding off any nasty surprises on the trip.

The Canenguez sisters wanted to know about luggage restrictions on Grupo Taca, El Salvador's airline. They were planning to take gifts for their relatives, and they worried about exceeding the airline's luggage limits. Two 50-pound suitcases to check and one 20-pounder to carry on, Cavero said, warning that the airline was going to be changing its policy soon.

Once customers like the Canenguez sisters find their way into the office, owners of these Hispanic agencies hope they'll return for other services. With the profit margins on travel small, many ethnic agencies will "try to offer as many possible services as they can to the market," said David Abraham, vice president of Bethesda-based Dan Travel.

"In the Latin American market everything stays among your own. It's a very loyal market," said Abraham, whose Argentine father and Portuguese stepmother run the agency with offices in Gaithersburg and Manassas.

Junction, housed inside a converted theater in Historic Manassas, finds itself catering to another growing sector. "We have a more affluent community than we did 10 years ago," said Stephen Nelson, president of the 23-year-old agency his parents founded.

His agency recently sold a two-week trip to South Africa to a customer and his daughter. A couple purchased a trip to Australia for their honeymoon. A family booked seven cruise ship cabins for their family reunion instead of asking a relative to host the annual event at their home, Nelson said. Local companies often book trips to the Caribbean or Florida as incentive for employees to meet their annual corporate goals.

A larger, wealthier population in the county means more travelers, he said, who can afford several quick jaunts a year instead of one long annual vacation.

The elimination of airline commissions has been hard on agencies. In 2000, there were 30,077 retail travel agent locations and corporate travel agents around the country accredited by the Airlines Reporting Corp., an organization owned by airlines. Last year, that number dropped to 20,876.

Airlines Reporting, which provides ticket distribution and other services for the carriers, doesn't keep tabs on the number of ethnic-owned travel agencies, but many Hispanic travel agents in the region believe such businesses are proliferating because of the increasing immigrant population, Abraham said.

Several Hispanic-owned agencies can be spotted along corridors of the county populated by Hispanic immigrants, such as Jefferson Davis Highway in Woodbridge and Centreville Road in Manassas.

Whether they will be able to survive in this niche remains to be seen. Claudia Romero, who along with her brother owns Monica's Services in Woodbridge, is considering getting out of the travel game and concentrating on the more profitable business of immigration services and money transfers.

"We don't focus on it because, truthfully, it's not that profitable," said Romero, a 22-year-old native of El Salvador who has lived in the United States for most of her life.

Luz Cavero, sales executive at Air World Travel & Training in Manassas, prepares airline tickets for Patricia Hernandez and Patricia Silva, who are traveling to Uruguay. The agency's array of services includes preparation of tax returns. Silva checks out the digital image Cavero has taken of her.