The Aer Lingus cancelation policy is extremely straightforward. You will receive an online or offline notification if Aer Lingus has to cancel your flight. You can either reschedule or cancel your flight when an airline cancels it. Reservations for Aer Lingus can be canceled up to two hours before to the departure time. You have the given window of time on your ticket to notify the airline of any cancellations. Depending on your fare class and cancellation period, Aer Lingus will impose a cancellation fee.
https://flightcancellationpoli....cy.com/aer-lingus-fl

You will have more flexibility, if you buy your ticket from British Airways. You can cancel your ticket and receive a refund under British Airways cancellation and refund policy. If you cancel your ticket within 24-hours of booking, British Airways will not charge you any cancellation fees.
British Airways cancellation policy states that there will be no fee if a passenger cancels their reservation due to illness or the death of a close relative. If you cancel your non-refundable ticket under emergency conditions, you are eligible for a refund.
https://flightcancellationpoli....cy.com/british-airwa