HAVANA (AP) — Just three days after the death of Fidel Castro, the first scheduled commercial flight from the U.S. to Havana in more than 50 years landed Monday to the applause of passengers and a water-spraying salute from firetrucks.

But the wheels didn’t even hit the ground before the warming ties initiated by President Barack Obama were thrown into doubt by President-elect Donald Trump, who has tweeted that he might “terminate” the detente. The travel industry, among others, hopes otherwise.

Passengers from Miami, wearing straw hats provided by American Airlines with the word “Cuba” on the back, were greeted with welcome signs in various languages, but no music. They arrived during an official mourning period, as Cubans packed Havana’s Plaza of the Revolution to join an homage to Castro, and a state-sanctioned live music ban hushed the capital’s usually festive nightlife.

The landing “was very emotional for me,” said Jonathan Gonzalez, 31, a Cuban-American born in Miami who said it was his third time visiting the island.

For decades, people thought it would take the death of Castro to open up travel to Cuba. In reality, restrictions on travel from the U.S. had already eased since Obama lifted some rules last year by executive order.

Several airlines began routes to other Cuban cities earlier this year. Later Monday, a JetBlue flight arrived in Havana from New York. Carnival Corporation launched its first cruise to the island this year, and Starwood Hotels became the first U.S. hotel brand to operate on the island.

Despite the relaxing of travel restrictions, going to Cuba isn’t exactly like hopping a flight to another Caribbean destination. Pure tourism remains illegal under U.S. regulations that allow 12 categories of travel to Cuba. They include religious and sports activities and educational travel promoting “people-to-people” contact — which is the clause most United States citizens travel under.

For Americans without family ties to Cuba, the most popular form of travel had been on tightly focused educational trips organized in conjunction with the Cuban government. The Obama administration lifted that group requirement in March, leaving Americans free to travel to Cuba as long as they can credibly describe their trips as educational.

What happens after Trump’s inauguration in January is murkier. “If Cuba is unwilling to make a better deal for the Cuban people, the Cuban/American people and the U.S. as a whole, I will terminate deal,” Trump tweeted Monday.

Some in the travel industry remain hopeful that Washington will keep its Cuba policies intact and that Havana won’t react by shutting off travel.

“I’m hoping there will be no knee-jerk reaction,” said Patrick Harrison, the chief marketing officer for Visit Tampa Bay, who is scheduled to fly on one of the first Southwest flights from Tampa to Havana on Dec. 16. “Obviously, I’ll be watching the news over the next couple of weeks.”

“It’s very difficult to put the genie back in the bottle. At the end of the day, business is business,” Harrison added. “Disruption is the only thing we dislike in the tourism industry. Disruption causes uncertainty.”

“We’ll see what will happen with the Trump administration,” said Alfredo Gonzalez, American Airlines’ director for the Caribbean. “We don’t know exactly what will happen, but we can say that we are in Cuba, in the provinces, in Havana, and we will continue our service moving forward.”

Paul Fletcher, a wine consultant from Naples, Florida, reserved a trip on the Carnival Fathom, an eight-day cruise that stopped in Havana, Santiago de Cuba and Cienfuegos. He said he had fabulous excursions, eating home-cooked meals in private restaurants, visiting cemeteries and learning the history of the island.

He booked the trip in part because he feared Trump would be elected president and would impose travel restrictions again.

“This might have been our one and only chance,” Fletcher said.