Dublin Airport has two terminals – Terminal 1 and the newer Terminal 2. Aer Lingus, United, American Airlines, Delta and Emirates use Terminal 2 while all other airlines use Terminal 1. On average the security queues in Terminal 2 are shorter than those in Terminal 1 although normally there is only 5 or so minutes difference. What many people don’t realise is that you can use either security queue no matter which airline you are flying – both ‘terminals’ are linked airside. If you are checking bags or need to check in at the airport you will need to go to the listed terminal for the airline.
If you are flying Ryanair for example and have checked in online with hand luggage only you can use the security screening in Terminal 2 and then walk to your gate. In fact, past security there is no such thing as Terminal 1 or Terminal 2. Aer Lingus flights often depart from gates that most people would consider to be part of ‘Terminal 1’.