FORT LAUDERDALE, Fla. — Passengers arriving at Fort Lauderdale-Hollywood International Airport on Saturday were still being dropped off for flights that no longer existed — learning only at curbside that Spirit Airlines had shut down overnight.

“I just found out,” Ricardo Tejeda said after stepping off a shuttle.

Within hours, thousands of flights had been canceled, leaving travelers stranded midtrip or scrambling to rebook as the airline halted operations with little notice. Check-in counters sat empty, customer service lines were unavailable and many passengers said they had received no warning before arriving at the airport.

Here’s what to know about what happens next and what travelers can do right now.

Refunds promised, but some may have to wait

In its official announcement, Spirit Airlines said the shutdown took effect immediately and urged passengers not to go to the airport.

The airline said it will automatically refund tickets purchased directly with a credit or debit card, while those who booked through third parties must contact their travel agent.

Compensation for customers who used vouchers, credits or loyalty points will be determined later as part of the bankruptcy process.

Loyalty points may be worthless

Clint Henderson, a travel expert with The Points Guy, said many Spirit Airlines customers could see the value of their loyalty points vanish, with little chance of recovering them.

“Basically, if you have Spirit points from the loyalty program, those points are essentially worthless,” he said. While travelers can file claims in bankruptcy proceedings, those tied to points are likely to be last in line for payment, assuming any money is available.

For passengers still waiting on refunds, Henderson said, one of the most reliable options may be to dispute charges through their credit card company, which can reverse payments for services not delivered.

Henderson advised travelers to act quickly and plan ahead to combat rising costs, noting that booking flights months or even up to a year in advance can help lock in lower fares. Tools that track price drops and offer credits may also help offset costs.

At the same time, broader industry trends are pushing prices higher, Henderson said. Airlines have been raising baggage fees, adding fuel surcharges, particularly on international award travel, and cutting less profitable routes, which reduces the number of available seats.

“The same amount of people want to travel this summer, and there’s fewer available seats for them, and that is a recipe for price increase,” he said.

Henderson also urged travelers to have a backup plan when flying. This means knowing alternative routes or even other modes of transportation.

Airfares could rise

Going.com spokesperson Katy Nastro said it’s “a sad day for anybody that loves affordable flights,” warning that the loss of Spirit Airlines could drive up fares by 15% or more on the routes that it used to fly.

“Leisure destinations like Orlando, Las Vegas, markets like Fort Lauderdale, those immediately are going to see the biggest impacts,” Nastro told NBC News, noting that those were among Spirit’s busiest hubs.

She said the budget airline helped keep prices in check by putting pressure on larger carriers, and without it, that pricing floor could disappear.

Demand, she added, is likely to shift to competitors such as JetBlue, which announced new routes Saturday that include additional flights to Fort Lauderdale.

What other airlines are doing to help

Airlines and travel companies are stepping up to absorb the disruption. United Airlines said it is offering capped “rescue fares” to stranded Spirit Airlines passengers, with most tickets priced at $199 and some longer routes at $299 for the next two weeks. Travelers must book through a dedicated webpage — not at airport counters — using their Spirit confirmation details.

American Airlines has rolled out similar discounted fares on routes it shares with Spirit Airlines and is weighing adding more flights and larger aircraft.

Budget carrier Avelo Airlines is advertising deep discounts, including up to 75% off base fares as it looks to attract stranded travelers. Outside of aviation, Hertz said it is offering one-way rental deals, allowing travelers to drive between cities without needing a return flight.

Delta Air Lines said it has filed reduced, nonrefundable rescue fares in affected markets for the next five days, including on near-full flights, across its domestic network and some U.S.-Latin America routes.

JetBlue is offering $99 one-way rescue fares for some stranded travelers and capping prices on key routes.

Travelers caught off guard

For some passengers, the shutdown wasn’t something they tracked in the news, but rather news they discovered in real time as they arrived at the airport.

Tejeda, 72, said he learned his flight home was gone only after reaching the airport, moments after returning a car rental. He had traveled to South Florida for medical reasons and said he relies on low-cost flights to move between places on a fixed income.

Angela Moreno drove from Miami early Saturday to catch a flight to Nashville for a family wedding, only to learn hours before departure that her flight had been canceled. By the time she arrived, she said, replacement tickets were already out of reach. She said flights on other airlines were going for as much as $600 — far more than she originally paid.

“We’re missing a wedding,” she said. “There are many people who cannot attend now.”

The disruption has rippled beyond vacation plans. Leonard Strobel, a freelance chef who travels frequently for work, said he had spent hours on the phone trying to use a flight credit for a surprise Mother’s Day visit before being reassured his flight was fine. He discovered later through the airline’s app that all flights had been canceled.

“I don’t know what to do now,” he told NBC News over the phone on Saturday. Strobel added that he is now considering a 15-hour drive to reach his family.

Airline workers are also grappling with the company’s collapse. Alexis Sharps-Watson, a former Spirit flight attendant who had been furloughed in recent months, said the shutdown was “devastating” for colleagues, many of whom live paycheck to paycheck.

“Not everybody has savings,” she said. “It’s just hard for everybody right now.”

On social media, flight attendants shared heartfelt posts mourning the loss of a job they described as a family.

Unions representing about 2,000 pilots, 5,500 flight attendants, mechanics and other employees laid off by Spirit called on its leadership and the government to ensure workers receive the compensation and benefits they are owed.