The invention relates to an aircraft (e.g. Unmanned Aerial Vehicle) and a main body thereof and an outer shell for the main body. The outer shell has: an inner cavity, the inner cavity having a space for at least accommodating main body components of the aircraft; and an outer surface, the outer surface enclosing the inner cavity and being bounded by a closed envelope surface. The main body includes the outer shell and the main body components accommodated in the inner cavity of the outer shell. The aircraft includes the main body, and a mechanical arm and/or a leg.