Airlines continued to operate flights to Paris on Saturday, but the terror attacks in the French capital left tourists and business travelers wondering whether to cancel upcoming trips.

The attacks left the travel community on edge. Some would-be travelers quickly canceled trips to Paris, while the airlines let anxious customers with weekend tickets for Paris change plans without a fee.

Tensions were high at airports across Europe on Saturday.

A Paris-bound Air France jet was evacuated at Amsterdam’s Schiphol Airport after authorities received a threatening tweet. At London’s Gatwick Airport, a terminal was shut down for hours after a 41-year-old man from France was seen throwing away what looked like a gun. Authorities called in explosives experts.

U.S. authorities said that they had nothing to add to Friday night’s comment by Homeland Security Secretary Jeh Johnson that officials didn’t know of any specific or credible terror threats against the United States.

Air France said it would operate all upcoming flights to and from France but that delays were expected because of increased security measures at airports, including Paris’ Charles de Gaulle Airport.

United Airlines and Delta Air Lines said that all their flights between the U.S. and Paris were operating, although Delta noted that many Paris departures were held up waiting for passengers to go through extra security screening. American Airlines said all its flights would run too, except a Paris-to-Dallas flight — that plane remained in Dallas when the Paris-bound leg was canceled Friday night.

Delta spokesman Anthony Black said flights to and from Paris were full. United and American declined to give details on the occupancy levels of their flights.

Some Americans, however, canceled trips after seeing coverage of the terror on Paris streets.

Joe Nardozzi, a 31-year-old New York investment banker, and his wife won’t be taking the wedding-anniversary trip they planned later this month.

“I have no interest in losing my life over a trip to Paris,” he said.

U.S. airlines waived fees for Paris-bound passengers who want to change their ticket, but only if their flight was scheduled in the next couple days. That angered Nardozzi, who paid $1,600 for his tickets and said American Airlines was too inflexible given the horror of the situation.

Blake Fleetwood, president of New York-based Cook Travel, said about 10 customers told him they want to cancel Paris trips. He and his wife might do the same next month.

“It’s a terrible situation,” Fleetwood said. “It’s going to hurt the travel industry, the hotels, the airlines, the restaurants.”

Kevin Mitchell, who runs an advocacy group called the Business Travel Coalition, expects some worried corporate travelers to cancel trips to Europe.

“These companies have to continue to do business,” he said, “but for some period of time they’ll give employees a lot of leeway about traveling to Europe and Paris in particular.”

It’s not just Western visitors who might avoid Paris. Egyptian college graduate Aya Sayed has always dreamed of strolling the streets of the City of Light.

“I would be too afraid to go because I don’t want to be mistreated because of my headscarf or ethnicity.” she said. “Who knows what they might do to us now?”

Decisions by leisure and business travelers could hinge on whether the Paris attacks are seen as a one-time event or the vanguard of a stepped-up campaign by Islamic radicals. Islamic State, the group fighting in Syria and Iraq, claimed it bombed a Russian passenger jet last month over Egypt’s Sinai Peninsula, although investigators have not determined the cause of the crash that killed 224 people.

Consumers with travel insurance that includes terrorism coverage can probably recover the cost of a trip to Paris, according to Squaremouth, a policy-comparison website. But even policies that cover terrorism may only apply to trips scheduled in the next week or month and might not apply to travel in other parts of France or Europe more broadly, a company spokeswoman said.

French officials said they would increase border controls on roads, train lines and at airports, which remained open.

Even travelers who go to Paris are likely to be in a less celebratory mood. On Saturday, the Eiffel Tower, the Louvre and other must-see attractions were closed until further notice, and the mood in the city was changed.

Toronto residents Mark Hutchison and Ashleigh Marshall planned a big night out during a Paris stopover on their trip back home from Tanzania — “go to a restaurant, go to a bar, have a glass of wine,” Hutchison said. Instead, they decided to hunker down in their hotel with a bottle of wine once the sun went down Saturday evening.

“It’s a lot to take in,” he said of the deadly attacks. “You can’t make sense of it.”

(AP)