33.99 km per 1 kg
In that flight, Yurii Yakovlev flew alone, using neither an autopilot nor even a toilet. After 9 hours and 6 minutes of flight he had 887.3 kilometres behind, having travelled along a closed triangular route. Yet, he burned only 26.1 kilograms of fuel, setting a world record of fuel efficiency — 33.99 kilometres per 1 kilogram of fuel. According to the information confirmed by the International Aviation Federation, this flight has set a world record as the longest flight on a fixed amount of fuel.