A dynamic soaring maneuver provides an aircraft with a solution for a long-endurance flight by harvesting energy from atmospheric flows. Incremental work and energy analysis of flight dynamics are carried out with the help of staircase function approximating a wind profile. The condition for a successful dynamics soaring is derived showing that the energy gaining maneuver depends upon the lift-to-drag ratio and the ratio of the speed of the vehicle to the wind speed gradient. For the three degrees of freedom model, the equations of motion are non-dimensionalised and solved numerically providing optimal flight trajectories using pitch and roll as control parameters. Dimensionless wind gradients were calculated providing an energy neutral cycle for ranges of dimensionless aerodynamic design parameters. Reynolds and Mach number similarity criteria were expressed in terms of the scaling parameters. Obtained expressions impose conditions on the mass and the planform area of sailplanes. These results make it possible designing flight experiments in Earth’s atmosphere that would represent flights on other planets, such as Mars, Titan, or Venus. As an example, a sailplane designed for dynamic soaring in Martian lower atmosphere was sized for flight experiments in jet streams at high altitudes on Earth.