Does Aer Lingus actually weigh the carry on luggage/.

Having flown back & forth US-Ireland on Aer Lingus twice in the past 2 years, we never had our carry-on bags weighed -- or measured, for that matter. Ditto for Aer Lingus partners flying onward to/from Europe and the UK. However, we weren't pushing the carry-on limit.

For checked bags, they do go on a scale when you deposit them at the airport check-in counter, before they are put on the conveyor belt.

Just follow their rules and you can travel without worry. If you are a pound overweight and they make an issue, take a pound out and stick it in your jacket pocket. Then put it back before you board.

I can only tell you my recent experience.

I flew Aer Lingus Newark-Dublin-Glasgow on September 8, 2016, and Liverpool-Dublin-JFK on September 19, 2016. I used carry-on only, with a suitcase and a personal item that met Aer Lingus's rules. My bags were not weighed or measured on any of the flights.

Of course, that's no guarantee for you. I agree with the others - be prepared for what you will do if your bags are weighed or measured.

The carry on rules for Aer Lingus are here: https://www.aerlingus.com/travel-information/baggage-information/cabin-baggage/

It would be smart to give them a call on your concern. I know from experience their rules vary depending if you are flying within the UK vs the rest of Europe, as I found out flying from Dublin to Birmingham back in 2014. Their carry on rules at that time was ridiculous as far as what you could carry on from Ireland to the UK

Thank you everyone for the replies!

3 flights last summer, we checked what is usually our carry-on . I read their website rules and didn't want to take a chance, but everyone else seemed to be carrying on bags the same size as ours. I didn't see anyone being weighed or measured.