I'm flying in July 2024 from London to Dublin with Aer Lingus; I have an EU identity card. I took for granted there would be no issue but I just checked on
https://www.aerlingus.com/prepare/passports-and-visas/travel-to-from-britain/
which says that "To travel between Ireland and Britain with photo identification other than a passport, you must be a citizen of either country."
The little digital tool they provide on the same page says that in fact my passport is required (but would not be required to travel from France to Ireland, say). I think that digital form fetches information from TIMATIC, but it links to something called SHERPA.
I called Aer Lingus call centre who said that my ID card is fine, but when I mentioned what's on the website then the service agent confirmed that my passport is required, and suggested I check on IATA travelcentre website. I just did, and there it says that my EU ID card suffices (by the way, on the form which I filled in they also ask which airline I'm flying with!)! I am very confused.
By the way I must add that neither the Aer Lingus website nor the digital tool they provide for checking entry requirements, is very professional. For example, for travelling Dublin to London, neither mentions that EU ID card is enough for people with Settled Status under the EU Settlement Scheme (this information, by the way, does indeed appear on the travelcentre website). Also, that tool on the Aer Lingus website says that passport is required to travel UK to France, ridiculous!
UPDATE I'm starting to get answers which don't solve my original question, so let's rephrase it this way to make it more clear: if I'm denied boarding by Aer Lingus and I complain with an EU or UK aviation authority then am I entitled to compensation?