The airplane selected for this 8-hour journey was way too small! It was uncomfortable, cramped, and not to the usual standards. A long-haul transatlantic flight needs to have more space and adequate overhead locker space for carry-on baggage. We had to check our small carry-on and they were the very last bags to arrive at baggage claim, 40 minutes after arrival. On two occasions I counted 17+ passengers lining up in the aisle waiting to access the bathroom, as there were only 2 lavatories in the economy area. Staff were clearly frustrated and the crew had to ask passengers to sit down to avoid blocking the aisle... another point why the plane was too small for that travel duration. Turbulence was frequent, again something that is not as obvious on a larger plane. As an Irish citizen living in the US, I'm so disappointed to see the Aer Lingus standard dropping and will be likely looking for other carriers for my frequent tranatlantic travels.