Flight Keflavík International Airport departs from Reykjavik Keflavík International Airport at 07:40 and arrives at Copenhagen Copenhagen Airport, Kastrup at 12:55.
The flighttime is about 3h 15m. The distance travelled ("as the bird flies"): 4025 Km. So the average speed is roughly 1238 Km.
There is an 2 hour time difference between Reykjavik and Copenhagen