Spirit Airlines has ceased operations, bringing an abrupt end to more than three decades of flying that reshaped budget travel in the United States.

The Florida-based carrier said Saturday it had begun an immediate and orderly wind-down, halting all flights and closing customer service channels. For passengers, the announcement came with little warning. Some arrived at airports only to discover their flights had been canceled. Employees, many of them notified overnight, found themselves out of work as the airline’s operations stopped.

The company pointed to rising fuel costs tied to the ongoing war with Iran as a key factor behind the decision. Despite having navigated bankruptcy twice in the past, Spirit said the latest financial strain made it impossible to continue.

Over the years, the airline built its reputation on deeply discounted fares and a no-frills approach that forced larger carriers to rethink pricing. Its bright yellow aircraft and unconventional marketing stood out in a crowded industry. At its peak, Spirit operated hundreds of daily flights and employed around 17,000 people.

In a statement, the airline expressed pride in its role in pushing down ticket prices across the market, even as it acknowledged the sudden end to its service.

Federal officials moved quickly to address the immediate fallout. U.S. Transportation Secretary Sean Duffy said a reserve fund had been set aside to refund customers who booked directly through the airline. Travelers who used third-party services were advised to pursue refunds through those providers.

Several major airlines, including United, Delta, JetBlue and Southwest, have offered limited relief by making available one-way tickets priced at $200 for affected passengers who can show proof of purchase.

Spirit also said it was working to return more than 1,300 crew members to their home bases. Its final flight landed at Dallas Fort Worth International Airport after departing from Detroit Metropolitan Airport.

Discussions about a possible federal bailout had taken place in recent days, but no agreement materialized. Duffy said funding constraints made such a move difficult, even as the airline struggled through its second bankruptcy in under two years.