As concern about swine flu grows, many travelers have switched vacation plans from Mexico to other warm destinations.

Travel companies and airlines hope fliers won't become skittish about getting on a plane to go anywhere because of fears about the flu known as H1N1.

"I'm seeing a heightened sense of concern," said Marvin Weber, owner of Marvelous Travel & Cruise Planners in Plymouth Meeting. "Some people are sitting back and waiting to see what happens with the flu."

Newtown Square-based Apple Vacations Inc., one of the nation's largest sellers of air-and-hotel package trips, said only 11 percent of travelers who booked trips to Mexico had canceled since the swine flu outbreak.

Of the 11 percent, most postponed trips to Mexico until sometime later this summer, said Timothy Mullen, Apple senior vice president. Some changed to other destinations, such as Punta Cana in the Dominican Republic and Jamaica.

"We had a task force ready to handle a wave of cancellations to Mexico, which never happened," Mullen said. "Looking forward, we had more new bookings this week to Mexico than cancellations."

Nevertheless, the volume is down, he said. "Some people are postponing their decision for a summer vacation to see what happens."

Travel agents, including Kate Murphy of Uniglobe Wings Travel in Blue Bell and Ronnie Liadis of Liadis Travel in Newtown Square, said those canceling trips to Mexico were still going on vacations.

"People rebooked," Liadis said, "and cruise lines have eliminated port calls in Mexico on their itineraries."

TripAdvisor.com, an online travel group, said it had seen a 50 percent drop in Web searches for hotels in Mexico but a 30 percent increase in searches for hotels in the Caribbean.

"I haven't seen people too afraid to go anywhere," said Bill Rubinsohn of Rubinsohn Travel in Jenkintown.

"Nobody has said to me, 'I'm afraid to get on an airplane,' " said Kari Thomas, president of Will Travel in Langhorne. "But the phones have been a little slow with new inquiries."

The travel industry was irked by Vice President Biden's suggestion this week that people should avoid air travel and mass transit because of the flu outbreak.

Biden told NBC's Today show that he had told his family to avoid air travel. Airlines and tourism have already been hurt by the recession, and officials worry that fears about the spread of swine flu will further discourage air travel.

As vacationers cancel or postpone trips to Mexico, airlines, including Continental and United, are halting flights there.

Continental, the largest U.S. carrier to Mexico, said it would cut 50 percent of its seats and flights to Mexico through flight reductions and use of smaller airplanes. United announced it would cut weekly round-trip flights to Mexico from 61 to 24 in May and from 90 to 52 in June.

US Airways, with 184 round-trip flights a week to 12 Mexico destinations, said it was cutting departures by 38 percent compared with its original May and June schedules.