During 1938, the RAF had begun to receive its first deliveries of the Hurricane and Spitfire monoplanes; an emphasis was soon placed on quickly reequipping half of the Gladiator squadrons with either of these monoplane types.[18] By the outbreak of the Second World War, the Gladiator had largely been replaced by the Hurricane and Spitfire in frontline RAF service. The introduction of these aircraft had been eased by the presence of the Gladiator, squadrons that had operated Gladiators prior to converting to the monoplane types experienced a noticeably improved accident record than those who converted from older types such as the Gauntlet. Experiences such as operating the Gladiator's landing flaps and familiarisation with its sliding hood have been attributed as having favourably impacted pilot conversion.[15]