Flight Keflavík International Airport departs from Reykjavik Keflavík International Airport at 10:30 and arrives at Copenhagen Copenhagen Airport, Kastrup at 15:35.
The flighttime is about 3h 05m. The distance travelled ("as the bird flies"): 4025 Km. So the average speed is roughly 1305 Km.
There is an 2 hour time difference between Reykjavik and Copenhagen