Your passport is your ID in Europe, so your passport will be checked at check in and at the gate, but this is not passport control or immigration, just an identity check, and it is very quick. There is no passport checks or immigrations checks between most EU countries (and Norway and Iceland). There is also no significant difference between the way EU citizens and non-EU citizens are treated in intra European flights. Only difference: EU citizens can use a national government-issued ID card for identification purposes at check in and at the gate, non EU citizens will have to use their passport, but the procedure is exactly the same.