LONDON -- Royal Air Force reconnaissance planes flew back from the island of Sylt today with photographic evidence of havoc created by wave after wave of British bombers in a six-hour bombardment of the German air base.

Dispatches from Toender, Denmark reported that two British reconnaissance planes, apparently on a photographing mission, also dropped three or four bombs in the middle of the island, then escaped westward with German pursuit planes chasing them. This was at 3 A.M. EST and other reports said there was renewed air activity and machine gun fire over Sylt at 9 A.M. EST. But no bombs were dropped.

Their pilots informed the Air Ministry that as dawn broke over Hornum, at the southern end of the island, hangars still were blazing and barracks smoking, and that evidence of severe damage to seaplane slipways was clearly visible.