I flew from Reykjavik Domestic Airport to Aykureri, Iceland today on Air Iceland Connect, a subsidiary of Icelandair. Besides being over three hours late--hello compensation--there was no security. You went straight from the check in counter to the gate. (Granted, it's a tiny building.)
I have flown internally in a few countries and always had to go through security. I was somewhat shocked.
There was, however, security for its one international flight to Greenland.