Allegiant air 24-hour cancellation （＋１ ８４４ ６０４ ２９４４） policy permits one to cancel the reservation within 24 hours. The good thing is that in such a case, no allegiant air cancellation fees will apply. Once 24 hours expire, a service charge will automatically apply if you cancel the booking. https://support.google.com/admanager/thread/306150911?hl=en