How to cancel a Ryanair flight within 24 hours? Ryanair cancel flight option within 24 hours is made for passengers who urgently need to drop their reservations due to any reason. Within 24 hours every cancellation is absolutely free and fully refundable. There are several methods of cancellation, the most popular being the online method, via the website, and the offline method where you can directly request a cancellation by calling on the customer care helpline. After 24 hours of booking a certain cancellation fee applies to all tickets and a refund depends on the type of ticket and the time left in departure.