Within the week, more than 400 U.S. college students will leave home to spend a study semester abroad in about 30 countries under a program called Experiment in International Living. These young men and women are evidence that at least some Americans have decided that the threat of Iraqi-fostered terrorism will not interrupt long-held travel plans. And apparently they aren't the only ones.

Although business and vacation travel to Europe, Africa and Asia has plummeted since the outbreak of war in the Mideast, Americans in customarily large numbers appear to be headed for such traditional winter vacation destinations as the resort islands of the Caribbean and the ski slopes of New England and the Rocky Mountains. Cruise ships in the Caribbean also seem to be doing a brisk business.

"People are still coming, and they are coming strong," says Patricia Peeples, a spokeswoman for Vail in Colorado, one of the country's largest ski resorts. "We feel very, very fortunate."

"The skiers are coming," echoes Bob Bailey, executive director of the Utah Ski Association, which represents 14 alpine and five cross-country areas. His only concern is that vacationers may not be spending as much for food and entertainment this year.

Indeed, in these close-to-home destinations -- including the Caribbean -- the impact of terrorism and the war actually has been less of a worry than the recession, say tourism officials. To lure cost-conscious travelers, a number of Caribbean hotels have introduced cost-cutting "fly-free" packages and other discounts this winter. Indications are the promotions will be successful.

"I can't single out any Caribbean island that is suffering," says Richard Ellis of GoGo Tours, a major tour operator in the Caribbean. In the first few days of the war, the normal pattern of reservations suffered what he describes as a "hiccup." People deferred their departures into February and March until they knew more about how the Middle East situation would develop.

"We've seen some fall-off to the Caribbean," says Tim Smith, a spokesman for American Airlines, a major carrier to the islands, "but nowhere near as dramatic as to Europe." He attributes the drop to the recession and particularly to its impact in the Northeast, usually a prime market for the Caribbean.

The abundance of good, skiable snow in the Rockies is regarded as an important factor in drawing near-record crowds at some resorts this season despite the shaky economy and war fears. At Vail, "Snow conditions are exceptional," says Peeples. Also, because of the weak dollar in Europe, American ski destinations have the attractive advantage of being cheaper than resorts in the Alps.

In contrast, U.S. airlines report that domestic business travel has remained sluggish, and the outlook for travel abroad -- vacation and business -- is even gloomier. In the past week, United Airlines and American Airlines were among domestic and international carriers announcing new reductions in flights to Europe and Asia, and some cruise lines began cancelling summer itineraries in the Mediterranean and shifting vessels to other ports.

The Crown Princess of Princess Cruises, for example, will spend the summer sailing the Caribbean instead of the western Mediterranean and the Black Sea. However, a sister ship, the Royal Princess, will remain in the Mediterranean and the Baltic -- an indication that Princess Cruises expects some demand for European vacations this summer.

As a new security measure, Princess Cruises has dropped its longstanding policy of permitting travel agents to inspect its vessels while they are in port. A while back, the firm reluctantly prohibited bon voyage parties that drew the family and friends of passengers aboard before departure. "The less people on a ship in port the better," says spokeswoman Julie Benson.

Since the Italian cruise ship Achille Lauro was hijacked by terrorists in the Mediterranean in 1985, major cruise lines have required boarding passengers to pass through metal-detectors, and luggage is screened by x-ray machines, according to Jack Estes, president of the International Council of Cruise Lines, a trade association in Washington. Most ports have the machines as standard equipment, as airports do, but some vessels carry their own devices because they call at less-visited ports.

Two more nations, Malaysia and Indonesia, have been added to the State Department's growing list of advisories warning of dangers resulting from the Middle East situation. The State Department also announced on Thursday that 70 acts of terrorism have been targeted against American and allied interests abroad since the Gulf War began. The attacks have caused property damage, but injuries have been few.

Because of terrorist fears, many Americans who might have planned to go abroad on vacation this summer can be expected to stay on this side of the Atlantic and the Pacific, especially if the Gulf War continues for any length of time. The same is true if the terrorist threat lingers long after the war is over, as one official of the Federal Bureau of Investigation predicted last week.

"We're just now beginning to see the ex-European business," says Tim Gallagher, a spokesman for Carnival Cruise Lines, which sails a fleet of "Fun Ships" in the Caribbean and along the west coast of Mexico. "Instead of a tour of Europe, they are booking a cruise. Last week alone, we picked up 12,000 people who booked a summer cruise."

The Greenbrier, a luxury resort in White Sulphur Springs, W.Va., says it is being flooded with calls from U.S. business firms that had planned European conventions but now want to hold them in the United States. "With the recession, it looked like we would have a bleak winter," says spokeswoman Sammy Baronner, "but now business is great."

Still, hope hasn't faded yet for tour companies doing business in Europe, which has been particularly hard hit by the drop-off in transatlantic travel.

"Exactly nothing is happening now," says Ewen Gillies, a spokesman for Globus Gateway Tours, which he interprets as both positive and negative. On the down side, very few new bookings for the firm's hefty catalogue of summer packages in Europe have come in since the war began. On the bright side, most people who booked early for the summer haven't cancelled. "We all assume they are waiting to see what will happen."

The Scottish Tourist Board is flying a 30-member delegation to the United States this weekend to begin a two-week sweep of the country promoting travel to Scotland. "The U.S. is our Number One market," says Graham Birse, director of public relations. "Because of that, we cannot afford to turn our backs." Usually, Scotland plays host each year to about 350,000 Americans who spend close to $200 million.

"We don't expect to be rip-roaringly successful this year," he says, explaining the reasoning behind the tour, "but the war has got to end. We believe we will be better placed when it does."

The delegation, representing 22 tourism organizations, plans to tell Americans that "the show goes on." Says Birse: "We're not bringing a message that Scotland is safe. We can't offer such assurances. But Scotland is quite aways away from the {war} theater, and our airport security is as good as anywhere in the world."

Obviously, security was an important consideration when the Experiment in International Living decided to proceed with its college semester-abroad plans, which get underway this week. "We got a lot of inquiries from a lot of parents concerned about their children going abroad," says spokesman Steven Malamud. But only nine cancelled out entirely after the war began, and 20 postponed their semester until later. The rest who had enrolled, 416 of them, should be on their way this week, if they haven't already departed.

"Our mission is to bring about peace and understanding," says Malamud, "and now more than ever this is important." Students are bound for Europe, Africa, Australia, China, Japan and Latin America. Based in Brattleboro, Vt., the organization has sponsored international educational programs since 1932. It is moving forward with other student projects, including summer study abroad for high school students.

As a precaution, the organization dropped four countries -- Morocco, Tanzania, India and Greece -- from its 1991 programs because of the potential danger from anti-American attacks. Students stay with local families, which, says Malamud, is considered a basically safe way to spend a semester overseas. They also are instructed to avoid political demonstrations -- good advice for any traveler -- and to keep a low profile. This means leaving at home any "I Love New York" T-shirts.

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Among war-related developments:

* Cruise changes: Because summer cruise bookings to the Mediterranean have been slow, some cruise lines have altered summer itineraries.

Princess Cruises originally had planned to operate two vessels in the Mediterranean. But it has decided to keep the Crown Princess in the Caribbean through the summer "because of the softness of demand," says spokeswoman Julie Benson. "We didn't feel the current downturn would allow us to have two big ships there. But reservations are still coming in."

Sun Line Cruises, which normally operates three vessels out of Greece, will shift its flagship, the Stella Solaris to the Caribbean also. The vessel will make seven-day cruises out of Galveston, Texas beginning April 27.

Elsewhere, Pearl Cruises has cancelled four winter and spring cruises calling on Bombay because of a State Department advisory recommending U.S. citizens defer all nonessential travel to India. Passengers get a full refund or can re-book for a future India cruise. And the Cunard Line has altered the 94-day world cruise of the Queen Elizabeth 2, now underway, to avoid transit through the Suez Canal.

Initially, several cruise lines that ply the Inside Passage to Alaska set Jan. 31 as the deadline for getting an early-booking discount. But Princess Cruises has extended the deadline to the end of March, and other lines may do the same. "People are a little preoccupied right now," says Benson.

At Princess and other cruise lines, normal cancellation policies are in effect. "We reassure passengers about our security. We tell them, 'If it's unsafe, we'll be the first to pull out,'" says Benson.

* Caribbean discounts: The temporary drop in hotel bookings in the Caribbean after the outbreak of the Gulf War prompted a number or resorts to offer discounts, among them fly-free packages, according to Richard Ellis of GoGo Tours.

For example, his firm is offering a seven-night stay at the luxurious Stouffer Grand Beach Resort on St. Thomas in the U.S. Virgin Islands for $895 to $1,455 per person (double), depending on choice of room. At that price -- set for lodging only before the war -- air fare is now included from Washington and other East Coast cities. For this and similar discount packages, contact a travel agent.

* Airline cancellations: United and American were among domestic and international airlines announcing cuts in international service because of the Gulf War.

United, which has more flights to the Orient than to Europe, trimmed its transpacific schedule because of the downturn in business and vacation travel abroad. "The Pacific has not been exempt," says spokeswoman Sara Dornacker. The carrier's three flights from Los Angeles to Seoul have been eliminated; the Newark to Tokyo nonstop has been reduced from seven to three times weekly; and on the Honolulu to Tokyo, there will be two flights daily instead of three.

At this time of year, American expects its planes to Europe to be flying at least 50 to 60 percent full. But current load factors are only in the high 30s and low 40s, says spokesman Tim Smith. As a result, the carrier will reduce the frequency of fights on eight of its eighteen routes to Europe, beginning March 2. Affected are flights out of New York, Chicago and Dallas to Paris, Frankfurt, Madrid, Stockholm, Zurich and Brussels.

While many people hesitate to fly abroad, the airlines continue to serve most destinations. Are the crew members and attendants under stress? "A lot of the public's concerns are perceptual and emotional versus realty," says Smith. "Our employes know the details of our security and are comfortable with it. As the public becomes more confident, some of that uneasiness will disappear."

* Security advisories: As a result of the Gulf War, the State Department issued travel advisories last week for Malaysia and Indonesia.

In Malaysia, the advisory reports, there is a threat of terrorist action against U.S. citizens and property. On Jan. 25, a bomb was found in an airline ticket office in Kuala Lumpur housing several American carriers. It was deactivated by police. In Indonesia, a "potentially dangerous" explosive device was found at the U.S. ambassador's residence in Jakarta, and Americans are receiving threatening phone calls.

Other war-related advisories currently are in effect for Israel, Sudan, Algeria, Jordan, Mauritania, Morocco, Tunisia, Pakistan, Yemen, Bangladesh, Djibouti, Qatar, United Arab Emirates, Saudi Arabia, Syria, Nigeria, Tanzania, India, Thailand, the Philippines, Malaysia and Indonesia. Several advisories recommend that Americans defer all nonessential travel to specified countries because they are in the war theater, and other advisories are precautionary warnings about possible anti-American demonstrations.

For the latest information, contact the Citizens Emergency Center, 202-647-5225. On war-related questions, you can speak directly to a State Department employe rather than listen to a recording.

In addition, travel agents have access to travel advisories on their computer reservation screens. And Travel Assistance International, a travel firm offering emergency medical assistance abroad to its subscribers, has opened its information line to the general public. To hear the travel advisories, call 800-821-2828 between 9 a.m. and 5:30 p.m. on weekdays.

In response to the latest advisory on Thailand, the Tourism Authority of Thailand has announced that hundreds of government troops have been placed on special security duty in the capital of Bangkok, the northern tourist city of Chiang Mai and the country's airports.

* Airport Immigration procedures: U.S. citizens arriving at John F. Kennedy International Airport in New York and Miami International may encounter new delays in processing through immigration. Until the outbreak of the Gulf War, U.S. citizens could bypass airport immigration desks under a special program at the two airports and go directly to the customs area. Now, however, citizens and noncitizesn alike must be checked by immigrations officials, according to Duke Austin of the Immigration and Naturalization Service.