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