Military personnel in the rear are usually called the rear detachment, and they are responsible for staffing, supplying, and maintaining the rear elements. The rear is considered a crucial part of military organization, and it can sometimes outnumber the unit's front line force by several times.[2]
In aviation, the term second line is used.[3] The expression second line generally relates to aircraft used for an air arm's own internal support functions, such as communications duties, target towing, navigational aids duties, and so on. Combat and transport aircraft are not generally included in the designation, although towards the end of their lives they can be relegated to second-line operations.