Spirit Airlines, the pioneering discount airline that shook up the budget travel business, is shutting down its operations.

The company is in its second bankruptcy and was in serious financial trouble well before the Iran war sent jet fuel prices surging. America’s eighth-largest carrier tried to reach a deal with the Trump administration on an 11th-hour rescue package, but a key group of creditors balked at the proposal.

Spirit is the first major US airline in 25 years to go out of business because of financial problems. Its demise has stranded thousands of passengers who have to adjust plans and millions who have tickets for future dates— Spirit canceled all flights, shut down its customer service and instructed customers not to go to the airport. Customers with Spirit tickets will be issued refunds, and they have been instructed to rebook travel on other carriers.