The main purpose of this article was to point out causes of reduced fuel consumption in aircraft jet engine when aircraft is in ground effect influence. Wing in ground effect occurs in the direct proximity of ground. The paper presents wing in ground effect description, with the numerical analysis of NACA M8 airfoil in three different conditions of flight. Numerical analysis was conduct in Ansys Fluent 17.2 software. The paper shows results of simulations which describes wing in ground effect influence on NACA M8 airfoil with two cases of jet engine exhaust gasses usage, first with exhaust gasses stream turns on upper airfoil surface, and second with exhaust gasses stream turns under lower airfoil surface. Results allow to define characteristics of NACA M8 airfoil in the influence of wing in ground effect which are lift coefficient, drag coefficient, drop of fuel consumption usage by the jet engine when lift force remains still in the wing in ground effect. The paper shows that in the wing in ground effect aircraft energy usage for flight in ground effect is smaller than for free air flight.