Objectives: The study analyzed the effectiveness of military pilots’ behavior under the influence of false horizon illusion – a false perception of the real horizon. It was assumed that visual illusion tends to cause spatial disorientation (SD). The question was asked which orientation of the sloping cloud (right/left) would have a bigger impact on SD. The effectiveness of the flight profile performance under the influence of visual illusion was analyzed in the context of the field dependence (FD), field independence (FI) or field intermediate dependence (FINT) of perception, the effectiveness of attention and operational memory. Material and Methods: The study covered 66 pilots. A flight simulator was used as a measure of effectiveness in performing the flight profile in spatial disorientation conditions. The effectiveness of attention and working memory was diagnosed using 4 computer tasks. Results: It was revealed that the right sloping cloud (compared to the left sloping cloud) had a greater impact on military pilots’ behavior. The cognitive style distinguishes the accuracy of the flight profile performance from the inclined cloud pointing to the right. The comparisons showed significant differences between the FI and FD pilot groups. All the pilots demonstrated the right-sided asymmetry of the flight rate. While performing tasks on the simulator, the FI pilots were characterized by a more stable rate than the FINT pilots. Conclusions: A general conclusion is that the “correct falling cloud” had a greater impact on pilots’ behavior. The presented results confirm the hypothesis that susceptibility to visual illusions is significantly increased in the pilots characterized by field dependence while the pilots with the FINT style of perception are characterized by a greater variability of the flight rate. Int J Occup Med Environ Health. 2019;32(5):653–62