In order to not risk producing an overpressure of air in the cabin of an airplane on the ground during servicing operation on the airplane, it is appropriate to deliver the air into the cabin of the airplane only when the inlets of the air-conditioning system are open. A device for feeding electricity and air to an airplane on the ground includes means of electric production capable of being connected to at least one electric circuit of the airplane and includes means of producing a flow of air. It has, in addition, a means of determining whether the airplane is actually switched on electrically or is not actually switched on electrically and means for inhibiting the flow of air delivered toward the airplane when the airplane is not actually switched on electrically, that is, as long as it is uncertain whether the inlets of the air-conditioning system are opened.