This paper addresses the Vehicle Routing Problem with Drones (VRPD), where the objective consists in creating shortest parcel delivery routes that are operated by a mixed fleet of trucks and drones. After formulating the VRPD as Mixed Integer Linear Program (MILP), we introduce a two-phase Simulated Annealing algorithm to solve the VRPD. Using benchmark instances, we conducted extensive computational experiments to prove the effectiveness of our algorithm. Additionally, we investigated the impact of using drones, not only on completion time but also on energy consumption of the truck-drone fleet under real-world resembling scenarios. Indeed, by optimizing for minimal makespan as well as minimal energy consumption, and by applying a bi-objective optimization model, the overall observation confirms substantial benefits of using drones on reduction of makespan and energy consumption. Thus, using a combined truck-drone fleet, last-mile logistics may become not only more cost-efficient but also more environmentally friendly and sustainable.