Reykjavik's domestic Airport to fly to places like North Iceland, East Fjords, and the West Fjords. The flights are crazy short and this airport is super small. There isn't even a secruity to go through. I recommend arriving 20 minutes before your flight. It's literally so easy to fly domestically in Iceland, it almost feels wrong.

Please note this is the Icelandair Airport. There are other airlines like Eagle Air, but their airport is on the other side of the runway.