In the present work we evaluate the accuracy of the Eucken formula and Stokes’ viscosity relation in high temperature non-equilibrium air species with electronic excitation. The thermal conductivity coefficient calculated using the exact kinetic theory methods is compared with that obtained applying approximate formulas in the temperature range 200-20000 K. A
modification of the Eucken formula providing a good agreement with exact calculations is proposed. It is shown that the
Stokes viscosity relation is not valid in electronically excited monoatomic gases at temperatures higher than 2000 K.