This paper presents an engineering calculation of the energy balance of a light passenger vertical take-off and landing (VTOL) aircraft for a reference regional route between Novi Sad and Novi Beograd. The mission profile is divided into vertical take-off, climb, transition, cruise, descent, vertical landing and operational reserve. For each segment, the required shaft power and energy are estimated using the adopted aircraft mass, rotor geometry, disk loading and propulsion efficiency. The analysis compares battery-electric, liquid-fuel piston and hybrid-electric propulsion concepts from the aspects of available energy, mass balance, peak power demand and practical feasibility. The numerical case study indicates that the reference mission requires approximately 189.93 kWh of shaft energy for a flight time of 53.25 min, while the vertical phases impose peak power requirements of about 265 kW. The results show that battery-electric propulsion is limited mainly by energy-storage mass, liquid-fuel propulsion offers a more favorable specific-energy basis, and hybrid-electric propulsion can represent a practical compromise if its additional system complexity is justified by mission range and power-distribution benefits.