The image of Imperial Airways as an organisation, and its iconic status in the Empire, hinged partly on its perceived efficiency and reliability, and partly on the impression created by its senior management. Indeed, Empire aviation traced the tiers, ceilings and colours of transport work in colonial shipping and railways. Promoters of Empire aviation, knowledgeable commentators and enthusiastic air travellers used maritime metaphors avidly. When the Empire-class flying boats entered service, Imperial instituted a new category of cabin crew to manage paperwork that included recording passenger and passport details, checking manifests of luggage, mail and freight, and handling customs documentation. British ground crews and support staff scattered around the Empire's airfields were probably reminded often about being representatives of their home country and its culture. Flagged aeroplanes and their flying crew came and went often, but ground personnel were more rooted.