Fuel consumption during the taxi phase of flight can be reduced by using electric wheel propulsion instead of aircraft engines. Currently, this can be either done by having external trucks towing the aircraft from the gate to the runway, or by incorporating electric motors on the aircraft wheels to power the aircraft without using the engines. The purpose of this research is to investigate whether a Hybrid Electric Taxiing System (HETS) that combines both technologies is feasible and yields better results in terms of sustainability, congestion and operation. First, a preliminary design phase of the HETS is carried out yielding the main characteristics of the system. An assessment model to study the feasibility of such system is then created by following a series of decision criteria, such as aircraft utilisation and taxi times at destination airports. Two scenarios are considered to examine the effect of the size of the network and fleet on the feasibility of HETS. The first case study includes flight data from the perspective of a single airline, while the second comprises data from five different airlines within an alliance. In conclusion, although many aircraft are eligible for the placement of electric motors, not many airports are eligible for the implementation of external vehicles. Moreover, although the introduction of HETS would lead to improvements on sustainability, it would increase airport congestion and require investments on the airport infrastructure that cannot be justified at the proposed scale.