Link performance of a hybrid radio frequency/free-space optical (RF/FSO) airborne communication system using the three-node cooperative architecture based on selection combination diversity is analyzed in this study. Using this architecture, FSO and RF links are simulated using the Exponentiated Weibull atmospheric turbulence distribution model under the mean aperture effect and Nakagami-m fading channel model, respectively. Closed form expressions for end-to-end performance indicators of this hybrid system are derived. The effects of turbulence intensities, modulation modes, and diversity communication schemes on the outrage probability (OP) and average bit error rate (BER) are analyzed using a simulation. The simulation results show that the hybrid RF/FSO airborne communication exhibits better BER and OP performances than the single FSO link system. Moreover, it is observed that low-order M-PSK modulation can effectively improve the impact of atmospheric turbulence on hybrid RF/FSO airborne communication system. When signal-to-noise ratio is high, the cooperative diversity communication scheme improves the BER performance of the system better than the low-order modulation scheme.