A usable drone is more than an airframe. Its main layers are the structure, propulsion, energy supply, flight-control electronics, sensors, communications and the equipment needed for its task. Suppliers may cover one layer or sell an integrated aircraft.
An integrator brings these layers together and is responsible for checking compatibility, documentation and the intended operating conditions. Manufacturing quality, maintenance, software support and the availability of replacement parts matter alongside headline specifications. This guide explains roles, not a bill of materials or assembly procedure.