Turbo-electric propulsive fuselage aircraft featuring Boundary-Layer Ingestion (BLI) are considered promising candidates to achieve the emissions reduction targets set for aviation. This paper presents an analytical method capable of estimating the BLI benefit at aircraft level, enabling a quick exploration of the propulsive fuselage design space. The design space exploration showed that the assumptions regarding the underwing turbofans and BLI fan mass estimation can have an important impact on the final fuel burn estimation. The same applies to the total efficiency assumed for the electric transmission, the range of the aircraft mission, and the propulsive efficiency of the engines used as benchmark. The regional jet and short- to medium-range aircraft classes seem to be the most promising as the ingested drag and power saving are among the largest, with long-range aircraft being just behind. The future introduction of advanced technologies, which target the reduction of vortex and wave dissipation at aircraft level, could increase the potential benefit of propulsive fuselage BLI. On the other hand, the potential benefit would be decreased if more efficient and lighter ultra high bypass ratio engines were used as benchmark.