Mission Aviation Fellowship (MAF) provides humanitarian aid using light aircraft to remote communities, separated by geographical obstacles or conflict. HumanAir aims to reduce their operating emissions by 50% while improving economic sustainability and maintaining operational versatility, by designing an innovative new aircraft within a timeframe of only 5 years. This report describes the design process and analysis of the HA-1 aircraft, the proposed solution to the problems encountered by MAF. The HA-1 aircraft achieves an emissions reduction of more than 50% while remaining competitive on cost, facilitated by the use of readily available Jet-A1 fuel instead of scarce leaded AVGAS. Therefore, the HA-1 will replace multiple of MAF’s ageing aircraft with a single sustainable alternative.