Climate-neutral aviation will require the use of alternative fuels such as Green Hydrogen and Sustainable Aviation Fuel (SAF) combined with the power density of an ultra-efficient gas turbine engine for the Short and Medium Range (SMR) aircraft market which corresponds to approximately 50% of the current share of air transport emissions. Rolls-Royce (represented within the HEAVEN project by RR-UK & RR-D) supported by key UK and European academia, industry and research centres are currently developing a new generation of very high bypass ratio geared engine architecture called UltraFan® which was started in 2014. From the beginning this ducted engine architecture has been designed to be scalable and meet the needs both of widebody and SMR markets. To achieve the necessary 20% fuel burn reduction Rolls-Royce proposes to significantly evolve the UltraFan design. The evolved engine architecture design will take the next steps in improving the efficiency of the gas turbine, take advantage of the properties of net zero carbon fuels such as Hydrogen to improve efficiency, combining this with Hybrid electric technology to reduce wasted energy. Numerous innovative enabling technologies already at TRL3 will be incorporated into this new architecture to improve the gas turbine efficiency. Together with work on Hydrogen in CAVENDISH (HRA-01) and Hybrid Electric in HE-ART (HER-01) Clean Aviation projects in conjunction with activities in national and regional programmes, this will be synergistically combined to validate up to TRL6 the highly innovative UltraFan design to support a 2035 EIS. HEAVEN brings together a highly specialised European industrial and academic consortium already strongly involved and familiar with the UltraFan programme. Additionally, the partner easyJet, European airline operator who have the largest fleet of European manufactured SMR aircraft operating in Europe, will bring an in depth knowledge of operational requirements and impact in this market.