Air travel is an important supplement to other means of regional transportation and in some regions the only viable solution. However, the regional transport market is highly competitive, and air travel must demonstrate that it can compete with hi-speed trains, cars or coaches. One major issue is the perception of the high CO2 and greenhouse gas (GHG) emissions by planes for these short journeys. Hybridization of the propulsion system enables combining the technical components benefits, thereby achieving an overall efficiency improvement. It is a concept well understood by the general public, due to the hybridization of automobiles, and can bring a real impact on the reduction of GHG emissions. While enabling rather than limiting new sources of energy in aviation, an ambitious path to reduction of greenhouse gases and the pathway to a cleaner and greener aviation for regional flights is built upon three pillars: • Electric hybridization • An ultra-efficient turboprop thermal engine • 100% SAF compatibility HE-ART will be a first step on the path to hybridization of regional aircraft and a reduction of up to XX% of GHG. This will be accomplished by achieving a strategic global objective of demonstrating, within 36 months, the viability of a hybrid electric thermal turboprop (e-TP) within the scope of a dedicated integrated ground test demonstrator. HE-ART will build on existing state of the art integrating the following technologies into the demonstrator: • Core thermal engine • Electric motor and power electronics • Gearbox • Propeller • Nacelle and heat exchanger This will be executed in conjunction with the Top-Level Aircraft Requirements that will be defined in parallel Clean Aviation research projects. To ensure that these requirements are met in full, HE-ART brings together the leading engine manufacturers, Rolls Royce and Safran with leading airframers, ATR, Airbus and Leonardo along with key manufacturers and research organisations.