Spirit Airlines has officially ended its operations, effective immediately, following a sudden cancellation by thousands of customers. The airline's app warned passengers not to go to the airport and that it could not help rebook travelers on other carriers. Refunds would be returned to the original payment form for flights purchased with a credit or debit card. This comes after a last-minute attempt to save the airline failed due to disagreements between the Trump administration and key bondholders. Industry groups had been pushing for a larger federal support for struggling low-cost carriers, arguing that without assistance, airlines like Spirit could collapse, leading to increased competition and increased prices. The company is entering a formal wind-down process.