Purpose Europe has adopted the Flight Path 2050 (FP2050) challenge demanding that by 2050, 90 per cent of the travelers are able to reach door-to-door destinations in Europe within four hours. A hypothesis can be formulated that without the Small Air Transport (SAT) system, optimized for short distances and for multiple but narrow passenger flows, this challenge cannot be met. Design/methodology/approach This paper defines design goals and necessary research focused on small aircraft concepts, as a required condition to fulfil the FP2050 challenge “90 per cent d2d 4h”. Findings The new small aircraft concepts have been defined as SAT Aircraft Family Program. Three demonstrators with common modules could be proposed: two using the same turboprop engine (first, one engine, 9 passengers; second, two engines, 19 passengers) and third demonstrator could be with a diesel hybrid engine. Research limitations implications The SAT Aircraft Family Program depends on demand optimized for specific regional features (passenger flows, passenger time value spectrum and infrastructure) and a set of matured technologies as a result of Clean Sky 2 (CS2) devoted to SAT. Practical implications This practical implications consist of developing on SAT technologies in CS2, deploying the demonstrators by the small aviation industry and launching an SAT system pilot phase. Social implications FP2050 has changed the approach to a citizen-oriented from an atomized technologies taxonomy-oriented one. The challenge “90 per cent d2d 4h” also covers the needs of remote regions. This niche could be filled by the SAT system using the small aircrafts family. Originality/value The paper value is in defining entry requirements, answering how to build the SAT Aircraft Family Program satisfying the FP2050 challenge “90 per cent d2d 4h”.

Over the last few years, teams from several research centres have been working on the concept of Small Air Transport, filling the niche between a regular surface transport and a scheduled air transport-on the distances over 200 km, utilizing numerous, though low in volume, passengers' streams-giving regions a chance to improve their communication capabilities. Small Air Transport's tasks are performed on small aeroplanes, which take up to 19 passengers, with a flight time of up to 4 h and at a reasonable price for a mass recipient. An important feature of the Small Air Transport system is personalization, which is flexible adaptation of the transport process to the customer's requirements and capabilities. This paper focuses on the selection and optimization of key parameters of aircraft fleet used in Small Air Transport. The research and analysis were based on the parameters of a reference aircraft selected for each individual class of small aircraft. Taking into account the data of currently used aircraft, the calculations were made to obtain the generalized transport costs per passenger kilometre. The generalized transport costs covers both-the total operating costs and value of time of passengers. As a result of minimizing these costs in terms of the variability of the key design factors of aircraft, the parameters of the recommended aircraft, in particular, classes were obtained. It was found that generalized passenger-kilometre costs for recommended Small Air Transport aircraft are only 20-30% higher than for regional aircraft (with the same load factor) and are more advantageous for Small Air Transport aircraft (lower cost) for small local passenger flows. Utilizing Small Air Transport aircraft, the profitability of air transport expands to significantly less intense passenger flows. The analysis allowed defining key design parameters of aircraft fleet in Small Air Transport in the initial phase of a project.