The law is clear in circumstances where an airline cancels a flight - for whatever reason - that all passengers booked on that flight who seek it are entitled to a full cash refund within 7 days. That provision is set out in EU Regulation 261 (2004). Notwithstanding the constraints arising from the COVID pandemic, a small number of flights are continuing to be operated. Where a flight takes place there is nothing in the law that entitles a passenger to a refund from an airline, but I understand that in such cases airlines are generally offering customers the chance to rebook or take a voucher in light of the covid-19 travel restrictions.
Anyone having difficulties securing a refund for a cancelled flight should contact the Commission for Aviation Regulation. Further advice is available on its dedicated passenger rights website www.flightrights.ie. The Competition and Consumer Protection Commission is best placed to offer advice on consumer rights generally related to travel at www.ccpc.ie .