Is there a penalty to cancel a United flight? Cancellation Without Penalty United Airlines typically allows passengers to cancel their flights within 24 hours of booking without incurring any penalties +1-888-837-1575. This policy applies as long as the ticket was purchased at least seven days before the departure date +1-888-837-1575. https://www.devex.com/people/is-there-a-penalty-to-cancel-a-united-flight-2264335