Background: The article addresses the issue of attitudes towards safety at work in the context of subjective variables such as psychological stress and the subjective self-efficacy of workers in the aviation sector. The research was exploratory in nature. It focused on capturing the individual experiences of ground handling staff at Polish and Slovak airports. Among the 326 people surveyed were engineers, firefighters, mechanics and electricians – a crew that works in difficult and threatening working conditions on a daily basis, often experiencing unexpected accidents and breakdowns. The psychosocial factors in industry 4.0 and this branch of industry itself are – according to the authors – verified empirically quite poorly. Taking care of safety at work and strengthening a positive attitude towards safety seems to be a key aspect of management in such units. Material and Methods: The Polish Questionnaire of Attitude towards Safety by M. Znajmiecka-Sikora, the Generalized Self-Efficacy Scale and the Plopa and Makarowski Stress Feeling Questionnaire were used in the research. Results: The statistical analyses carried out, including regression analyses and a model of analysis of mediation between variables, have indicated that this sense of effectiveness is a key positive predictor of every aspect related to strengthening attitudes towards safety (a cognitive aspect [β = 0.21, p < 0.001], an affective aspect [β = 0.15, p = 0.001] and a behavioral aspect [β = 0.15, p = 0.002]), as well as the overall level of attitude towards safety (β = 0.19, p < 0.001). Conclusions: The sense of effectiveness is an important mediator between the level of perceived stress and attitudes towards safety, which means that as the subjectively perceived sense of self-efficacy increases, the level of experienced stress decreases and thus the positive attitude towards safe actions and behaviors in the workplace is strengthened. Med Pr. 2021;72(5):479–87