Flight Keflavík International Airport departs from Reykjavik Keflavík International Airport at 01:10 and arrives at Copenhagen Copenhagen Airport, Kastrup at 06:20.
The flighttime is about 3h 10m. The distance travelled ("as the bird flies"): 4025 Km. So the average speed is roughly 1271 Km.
There is an 2 hour time difference between Reykjavik and Copenhagen