This summer promised to be a robust one for Europe's travel and tourism industry, with many destinations expecting a repeat of 2015's bumper crowds.
Lower airfares, fueled by a strong dollar and falling jet fuel prices, have made overseas travel more affordable. But Tuesday's bombings in Brussels are likely to cause many Americans to rethink their vacation plans and perhaps avoid Europe altogether.
The attacks at the Brussels airport and subway, which killed 34 people, including three suicide bombers, and injured 270 others, came as tourist season is getting underway in Europe and just ahead of Easter holiday celebrations.
British travel company Thomas Cook said overall summer bookings are lower than this time last year with just 40 percent of the summer season sold -- due in part to unrest in Europe.
Brussels' tourism sector had only just begun to recover from a tough winter following a five-day security lockdown in November, when Brussels feared an attack similar to the Paris assault that killed 130 people.
U.S. airlines had been poised to benefit from strong demand as Europe shifts into the tourist high season, but the Belgium attacks are seen renewing fears and are expected to cut into ticket sales. The three largest U.S. carriers, American Airlines (AAL), Delta Air Lines (DAL) and United Continental (UAL), derive at least 12 percent of total revenue from trans-Atlantic travel.
That exposure helped fuel losses on Wall Street as details of the attacks unfolded on Tuesday. United, American and Delta all traded lower Wednesday following drops the day before.
Brussels has long been a popular destination for Americans, with its friendly locals and fine beer and chocolate. Though less of a tourist draw than Paris or London, Brussels is nonetheless an important transportation hub. It's also home to NATO and several European Union agencies.
On Tuesday, the State Department issued a warning to U.S. citizens of potential risks of travel to and throughout Europe following several terrorist attacks, including the Belgium bombings. "Terrorist groups continue to plan near-term attacks throughout Europe, targeting sporting events, tourist sites, restaurants, and transportation," the agency said.
The fallout from Tuesday's bombings probably is likely to extend to travel demand across Europe, though it's too soon to assess the potential damage, said Savanthi Syth, an analyst at Raymond James Financial. Fewer arrivals from may also result in less demand for domestic flights to carry international travelers across the U.S.
Evidence of tourists' wariness of places where violence has flared is evident in Turkey, where summer hotel bookings have fallen 40 percent in the wake of a string of terrorist attacks blamed on militants. Industry figures show that hotel occupancy rates have plunged more than half, and hundreds of hotels, bed-and-breakfasts and boutique resorts have been put up for sale.
Rather than risk travel to Europe, many Americans are instead shifting their sights south to destinations such as Australia and Brazil, where Rio de Janeiro will host the 2016 Olympics.