Complex sentence: Despite this poor start, he rapidly became attuned to his aircraft and, as if in confirmation, over Verdun on 26 April 1916, he fired on a French Nieuport, downing it over Fort Douaumont, although once again, he received no official credit.
Split into simpler sentences: Despite this poor start, he rapidly became attuned to his aircraft. Over Verdun on 26 April 1916, he fired on a French Nieuport, downing it over Fort Douaumont, although once again he received no official credit.