'Bloody April' 1917 marked both the high and low water points of the Allied struggle for mastery of the air over the Western Front. The Germans, though inferior in numbers, were introducing superior machines and the Allies' pilots had to exert all their courage and tenacity to match and then beat the German effort

This article is located in the History of the First World War Volume 5 (REF D522 .H58 1969 V.5).