If you miss your Spirit Airlines flight, they consider you a "no-show," which means your ticket is canceled without a refund. However, you can try to fly standby on the next available flight if you arrive at the airport within two hours of your original departure—just be prepared to pay a fee. Another option is to rebook, but you'll need to cover the change fee and any fare difference. If you bought the "Flight Flex" option when you booked, you can change your flight once without the change fee. Sadly, without a flexible fare, credits or refunds aren’t usually an option. Go through the Spirit Airlines Missed Flight Policy for more details.