A main limitation of fully electric vehicles is their maximum range, which is principally constrained by the performance (i.e. energy density) of energy storage systems. A range extender, coupled to an electric vehicle, is a system able to store and/or convert energy that is supplied to the vehicle itself with the aim of extending its range. This work deals with the technological development and electrical sizing of a flight range extender concept for light electric aircraft. The presented platform, defined hereinafter as RExMoto, is based on the concept of modularity, obtained by embodying the range extender as a light-weight motorcycle. The benefits and technological challenges are described throughout and a detailed analysis in terms of operations and mission profile is provided. A legacy light aircraft is used as a case-study platform.