Flight Keflavík International Airport departs from Reykjavik Keflavík International Airport at 15:30 and arrives at Copenhagen Copenhagen Airport, Kastrup at 20:45.
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