If your flight is delayed or cancelled due to weather or other unforeseen circumstances, you are entitled to a refund that does not include the cancellation fee. Qatar Airways cancellation policy permits you to cancel your ticket at any time, whenever you want. If you do not meet the free cancellation standards, you will incur cancellation charges.
https://flightcancellationpoli....cy.com/qatar-airways

Unexpected changes to travel plans are not common. The Allegiant Airlines cancellation policy permits you to do so if you must cancel your flight for any reason. Allegiant Airlines will not refund your ticket or charge you a cancellation fee if you cancel within 24 hours after making your reservation. If you are able to cancel your flight inside the 24-hour window, there is no fee.
https://flightcancellationpoli....cy.com/allegiant-air